Note: one of my best friends is in this situation with her friends, so I'm asking this question for her (from her perspective).

I have two close friends, Bobby and Sarah, that I met together almost 3 years ago (we all met at the same place/time). Bobby and Sarah have been dating for almost two years now. Things are pretty serious between them. They both still have their own places, but there seems to always be an empty apartment.

At a party recently while she was pretty drunk, Sarah admitted to me that she slept with another man about a month ago1. I was shocked. Things (at least from the outside) seemed to be going well for them.

If I was only friends with either Bobby or Sarah, this would be easy. But I'm torn--I feel like no matter what I do I'm choosing a side and "betraying" one of them even though they're both close to me. That being said, I think that honesty is the best policy, so I've decided, as his friend, that this is something Bobby should know about. However, I know Sarah will likely be upset about a breach of trust.

How can I let Bobby know that he's been cheated on while minimizing the fallout for myself from Sarah? I love them both and I don't want to lose either of them to this.

1. In response to several comments about whether they may or may not have an open relationship: Sarah explicitly referred to what she did with the other man as "cheating," which leads me to believe that it was not something Bobby consented to.

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    What was Sarah's tone? Was it one of regret and did she indicate that she was desperate to remain with Bobby? Or was it more like she did it because she was fed up with or had lost respect for Bobby?
    – komodosp
    Commented Oct 9, 2018 at 16:11
  • 2
    @colmde she was pretty drunk and a little delirious when she told me, so it was difficult to read the emotions or tone very well. (not to mention I was slightly intoxicated as well, which doesn't help)
    – scohe001
    Commented Oct 9, 2018 at 16:26
  • 5
    Please don’t write answers in comments. It bypasses our quality measures by not having voting (both up and down) available on comments, as well as having other problems detailed on meta. Comments are for clarifying and improving the question; please don’t use them for other purposes. Instead, wait until you have enough reputation to answer the question. (cc @Antzi)
    – Mithical
    Commented Oct 11, 2018 at 7:14
  • Can you clarify whether you insist on letting Bobby know, or would different ways be acceptable?
    – gnasher729
    Commented Oct 12, 2018 at 21:33
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    @gnasher729 I'm not sure what you mean. Like I said in the question, the goal is to "let Bobby know that he's been cheated on while minimizing the fallout for myself from Sarah." How I let Bobby know is what I'm asking.
    – scohe001
    Commented Oct 12, 2018 at 21:36

9 Answers 9


Your question is how you can tell Bobby that he has been cheated on, so you have already decided that is the right thing to do. That is good, because we can't solve a moral dilemma for you, and we couldn't say whether or not you should tell Bobby.

Because you've already made this decision it is fair to say that your own personal moral code has told you that Sarah has done something "wrong" and that Bobby has a "right" to know.

Just for a moment imagine what could happen if you didn't say anything and Bobby later found out about it and learned that you knew all along. He probably wouldn't trust you anymore, and he'd likely assume that your covering it up either by deception or omission meant you took Sarah's side in the matter. In actual fact your conscience is telling you to say something to Bobby because you don't side with Sarah.

The reason I put that scenario to you is because at the end of all of this, no matter how people react (because there is no guaranteed method to minimise all possible fallout) you want to have a good conscience and to have stood up for what you believe is right. That can be worth more than holding onto a friend who doesn't share you stand on matters like this.

There are two possible outcomes from telling Bobby you should consider:

  1. He dumps Sarah because he cannot forgive her indiscretion, he may not take the news from you so well but in time he will probably thank you for telling him.
  2. He forgives Sarah and they stay together. This may result in them both pushing you away, because if they want to make a go of it as a couple, having someone around who knows a "dirty secret" might be a threat to that.

Also there are two possible reactions from Sarah worth considering:

  1. She eventually comes to understand why you had to tell Bobby, and you retain your friendship.
  2. She never forgives you and you lose her friendship. This could happen whether they break up or not.

I can't guess at the odds, but I would say that the scenario in which you are most likely to lose them both as friends is if you say something and they stay together. Even if they can understand why you did it and forgive you, it will just be awkward having someone around who knows that your relationship isn't as perfect as they want people to believe it is.

The best approach I can suggest is for you to speak to Sarah first and tell her that you believe Bobby has a right to know. If she agrees with that then you could tell her she has to tell him herself. Tell her that you feel you have a moral obligation to make sure he knows, and that only if she doesn't tell him will you have to tell him yourself.

This isn't a guaranteed fail-proof method, but I believe it is the one most likely to be successful because (i) you aren't doing anything behind Sarah's back, (ii) if she tells Bobby then he need never know you were involved, (iii) it alleviates your conscience and (iv) shows Sarah that your motivation is your conscience and a desire to do the right thing, rather than simply interfering in someone else's relationship.


This is the initial advice I gave my friend. We're still talking about how she should handle this, so I'm excited to see what you interpersonal adepts come up with! :)

You're right to fear Sarah becoming upset about a breach of trust, because you would be breaching her trust. You'd be taking something she told you in confidence (even if she was inebriated) and going behind her back to spill her secrets to Bobby. Because of this I'd tell Sarah directly that you're planning on telling Bobby.

Sarah's probably feeling some kind of mix of guilt, self-loathing, fear, and a whole host of other emotions. Depending on her personality, she may be one step away from turning all of that toward you as hate and anger. As such, I'd try to play to her empathy to you as her close friend by emphasizing how much you care about Bobby and her and how much it would hurt you to have to keep this secret.

I'd bring up the party and have a conversation about what happened--letting her vent her feelings about the whole thing. After she's gotten it all out, I'd let her know what you're thinking:

I don't think it's fair to Bobby to keep hiding this from him. I love you both and I don't feel like I can look him in the eye and keep hanging out with him if I have to hide something like this from him. I think it'd be better for both of you if he heard it from you instead of me, so I wanted to give you time to talk to him before I see him next1. I don't want to go behind your back or betray your trust with telling me, but this isn't something I can keep from him.

She might be mad. She might yell at you. Or she might feel defeated and seem to deflate. Either way, make sure you stay as calm as you can while handling her. If you think it'd be a good idea, you can offer to tell Bobby together with her if she needs the support.

1. Thanks to @JessK for this one!

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    I like this interpretation, although I would emphase encouraging Sarah to tell Bobby the truth, highlighting that you can't in good conscience keep such information from a friend, and that if you had kept a similar secret from Sarah (IE someone cheating on her) she would feel betrayed, a sort of 'how does Bobby feel about all this?' approach. If the relationship isn't a happy one, Bobby needs to know the truth. Commented Oct 9, 2018 at 14:11
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    I'd also emphasis that she needs to be the one to tell Bobby. Sarah already let the cat out of the bag once while drunk, it's only a matter of time before Bobby finds out. If their relationship is to have any chance of surviving this, Sarah has to come clean to Bobby herself. Mistakes and bad decisions are inevitable in any long term relationship. If the two of them can't overcome this together, their relationship's days are already numbered. If anyone else tells Bobby, they will then have to mend things with the relationship already on fire, and that's practically sabotage.
    – Tezra
    Commented Oct 9, 2018 at 18:15

I feel you!

I understand perfectly what you are going through, but my advice is to stay out of it. I know they both are your friends and you love them and care for them, but please don't choose sides and don't tell Bobby about Sarah, either Sarah about planning to tell Bobby what she did. It won't end well and for some reason maybe Bobby doesn't want to find something like that or maybe he won't believe you.

In the end, you might lose them both in your way to make things right.

Just take a moment and think.

You said that from the outside their relationship seemed to be going really well, but what if they are not? What if Bobby doesn't make Sarah feel good? Or what if their act is just too good that they don't realize how much they are lying? What if Bobby is the one pushing Sarah over the edge? What if Bobby cheated on Sarah too? What if?

There might be a lot of scenarios so don't jump to conclusions.

Since Sarah told you about that, she might felt really bad about that and that secret might be eating her up from inside. And somehow she felt like telling someone her deepest, darkest secret in order to free herself from the guilt. Maybe she tries to deal with the fact that she cheated on a good man.

If I were you, I'd stick with Sarah and make her see the truth before hurting Bobby more than she already did. But not trying to threaten her with: I will tell Bobby everything. Try to highlight to her how much they both mean to you, and that by telling you that secret, she made it hard for you to look at Bobby. Repeat her what she means to you and that you want her best. Tell her that her secret is safe with you. But in the end, Bobby will find out (karma) so she better tell him. Make her realize that her decision wasn't good and that if she misses something in her relationship she should end things before keep hurting Bobby. And try to make her tell you the real reason why she did that. Because there is always a reason behind every act!!!

Threatening someone even as a friend, is never ok. I know your intentions are good and pure, but she won't see it like that. She will see it as an act of betrayal. Be by her side and help her go through all of this. She trusted you with her deepest secret and that means you can't go simply to Bobby. As I said previously, there might be a chance that Bobby won't believe you or that he already knows.

Just trust the Universe and Karma and things will set the way they should. Just don't choose sides before knowing perfectly both sides and even then, you might not know the whole truth.

Take into consideration the fact that even after Bobby finds the truth, he might forgive Sarah, but not you. And in the end, you don't want to lose them both.

Ps: Be by Sarah and make her turn herself to Bobby but not by pushing her or threatening her. And be by Bobby's side too (by defeating him in front of Sarah).

Ps2: Make Sarah understand the burden and the huge amount of responsibility she put on your shoulders when telling you the truth. Now, because of her act, you have to lie and betray a friend in order to cover for her. And if she is a good person, which I vote she is, down there, she will take the quilt out of your shoulders and tell Bobby the truth on her own. And in the end, if this scenario happens, you will end with two best friends, not just friends!

Best luck!


I think you should have a follow-up conversation with Sarah.

While you may feel it’s your responsibility to tell Bobby, it is really Sarah’s. Sarah should be given the option since it was her transgressions that led her to the situation in both (1) challenging her relationship and (2) telling you about it.

Have a heart-to-heart with her about what she shared while you were indulging. Let her know your feelings about the situation, just as you have done here, and ask if she has any plans to share what happened with him. Don’t be judgmental or accusatory. People that engage in extra-relationship affairs often aren’t trying to hurt their partner and sharing it with you may have been a way of seeking help. Encourage her to talk with Bobby and that although you have no plans to abuse her trust, you think Bobby’s important and it would be all-the-more disrespectful to hold such information from him.

Note: what you say and how you say it is important. This is a delicate situation and the slightest misinterpretation could make devastating impacts on your relationship. For instance, it could also backfire and Sarah could maintain her relationship with Bobby and turn it all on you.


Since this is StackExchange, I'll made a sci-fi reference to convey my point: this is a real-life interpersonal Kobayashi Maru dilemma.

Something to consider is that not only did Sarah betray Bobby, she also forced you into choosing a side (a no-win scenario) by telling you. Others here have laid out all the permutations, but you really have no idea what consequences will happen.

We must first acknowledge that there is no way to control reactions of others in this scenario; due to this you must focus on minimizing the damage to yourself. Regardless of the consequences (which you have no control over), if you follow your own ethical headwinds you can at least hold your head high - content that you acted consistently with your internal value system.

The way you wrote the question, it appears that you believe you must tell Bobby. This is something I agree with for the following reasons:

1) Knowing nothing other than what was documented in the post, we can objectively agree that Sarah wronged Bobby in one of the worst possible ways.

2) Sarah also wronged YOU. She falsely assumed: [a] You will default to taking her side (an insult to your character) or [b] fails to understand that the burden of this knowledge forces you into an ethical dilemma.

3) Due to (1) and (2) above, we know that Sarah is consistently untrustworthy and selfish with respect to this this event. It's reasonable to conclude that she cannot be trusted to tell him without self-serving damage control that would only serve to mislead Bobby and prolong his hurt. Trickle-truth is hyper-common with cheaters and is a thing that must be acknowledged and prevented if your goal is to truly do right by Bobby.

Side commentary: I would let Sarah know WHY you acted on the information (after the fact). Sarah appears to be so enveloped in her own solipsism that she needs this overtly explained to her. She obviously does not appreciate or understand the dilemma she put you in.

TLDR: tell Bobby everything you know and then step out. Assume you may never talk to either one again. Remember it's a no-win scenario that is custom-built to test your character.

Edit: per commentary below, this has been edited to further detail my thought process.

  • 4
    You wrote: we can objectively agree that Sarah wronged Bobby in one of the worst possible ways. That is hardly uncontroversial. Being cheated on (and not knowing it) does not ruin your life. It likely won't make you less happy. It won't physically hurt you (unless your SO failed to use protection). But being cheated on and knowing it is indeed a severe blow. Make of that what you will.
    – piojo
    Commented Oct 12, 2018 at 8:11

There are several missing bits of knowledge that are not presented. We know these two people are not married and not even living together. We don't know what their expectations are from the relationship. We don't know if one (or both) of them are not ready for a longterm emotional and economic relationship. The fact that they maintain separate residences suggests they have not in fact made a commitment to a lasting sexual and/or emotional relationship. They may never have discussed what level of commitment they share or expect of the other. Or they may even have divergent understandings of the other's commitment to monogamy.

You seem to be making an assumption that Bobby understands that a joint commitment has been made to maintain at least temporary exclusivity on a sexual level. And you are also assuming that honesty with Bobby requires you to share knowledge with him. You should re-consider where this assumption comes from. Is it possible that this moral posture is really what you would expect in a relationship, but not necessarily one that Bobby expects?

If you feel the need to talk to one of them, it should first be with Sarah. Say simply that you wish you had not been given this information and you feel uncomfortable keeping it from Bobby. I'm not, however, sure you have the right to even ask about the level of commitment in their relationship. It's really between them and them alone whether they want to share that personal information with you. That will inform your next steps. It might result in Sarah `fessing up if there was a (broken) understanding of exclusivity. Or it might clarify where she sees the relationship going.

  • 3
    FYI, OP clarified in a comment that Sarah herself called it cheating (just edited it into the post, so sorry if you missed that before!). Does this affect your answer?
    – Em C
    Commented Oct 10, 2018 at 2:55
  • It might inform how the discussion with Sarah could proceed, but little else.
    – 42-
    Commented Oct 10, 2018 at 7:04
  • 1
    Could you elaborate on what you mean by that? Since the question is about having that discussion with Sarah, it'd be helpful to sketch out some of the likely directions it could go and what OP could do. I think I understand that you're asking OP to verify the situation first, right? but I'm confused as to when / how they're achieving their goal of letting Bobby know that Sarah cheated.
    – Em C
    Commented Oct 10, 2018 at 11:27
  • I'm not convinced that "letting Bobby know" should necessarily be a goal. Remember this is really a friend of a friend who is asking the question. The goal should be to get clarity about Sarah's understanding of the relationship. Does she feel she really does have a commitment to monogamy? Does she think Bobby also feels a commitment? Does she now want the relationship to continue? Does she think that "total honesty" will improve the relationship?
    – 42-
    Commented Oct 10, 2018 at 15:19
  • In response to the "friend of a friend who is asking...": I had my friend with me when we were writing up the question, so these are mostly her words. Before responding to comments on the question for clarification I've been texting her and repeating her responses almost verbatim. In other words, I've been doing everything I can to make this a question from the friend and not the "friend of a friend"
    – scohe001
    Commented Oct 10, 2018 at 15:23

Ah, moral dilemmas. I believe some other poster said something similar, but consider a Machiavellian perspective. From chapter 21 of Niccolo Machiavelli's The Prince:

A prince is also respected when he is either a true friend or a downright enemy, that is to say, when, without any reservation, he declares himself in favour of one party against the other; which course will always be more advantageous than standing neutral; because if two of your powerful neighbours come to blows, they are of such a character that, if one of them conquers, you have either to fear him or not. In either case it will always be more advantageous for you to declare yourself and to make war strenuously; because, in the first case, if you do not declare yourself, you will invariably fall a prey to the conqueror, to the pleasure and satisfaction of him who has been conquered, and you will have no reasons to offer, nor anything to protect or to shelter you. Because he who conquers does not want doubtful friends who will not aid him in the time of trial; and he who loses will not harbour you because you did not willingly, sword in hand, court his fate.

Niccolo Machiavelli is considered many things: a diplomat, politician, historian, writer, playright, poet, and a philosopher. However, he is also considered a humanist. Although this quote of his refers explicitly to war and, in particular, taking a side versus remaining neutral, this theme also exists in relationships.

Speaking analogously, there is no way to completely win in war, be it a war between your allies, enemies, or both; there will always be losses. After all is done, whether you sided with the conquering side or the conquered side, there is something that you will have lost:

  • if siding with the conquering side, you will have lost all respect and favor from the conquered side;
  • if siding with the conquered side, you will have lost all respect and favor from the conquering side, and you will be destroyed.

In choosing one side, you will undoubtedly be hated by the other; you will be singly hated.

Remaining neutral involves detriments as well, worse so than having chosen a side:

  • the conquering side will both view you as disloyal for not having supported them, and the conquered side will view you as disloyal for not having lost with them.

You will be doubly hated, from both the conquered side and the conquering side; a worse fate than being singly hated.

So what must a prince do? He must come to the understanding that in war, there is always loss. Moreover, he must understand that remaining neutral is doubly worse than choosing a side. Thus, he must choose a side.

In another, less elegant way of putting it, someone's gonna get hurt regardless of the decision you make. At the very least, you can control some of the damage and choose to reveal what you heard from Sarah to Bobby. And I'm sure you've heard enough quotes by now, but let me give you another one: "all it takes is one bad apple to ruin the bunch". Unfortunately, Sarah was the bad apple and she ruined not only her relationship with Bobby by cheating on him, but also with you by telling you the truth and placing this burden upon your shoulders. She created a "war" and now all will suffer (to varying degrees).


I've been where you are, and it's horrible. You have my sympathy. It's a bad situation, and there are no good options for you, but you need to pick a side. You might be able to stay friends with both, but you should go forward under the assumption that you cannot.

Imagine you didn't have this information, and fast forward 2 months: Bobby and Sarah have broken up because he found out about it. Where do you stand? Sure you want to stay friends with both, but when push comes to shove and they both invite you out on the same night, what do you do?

My situation was slightly different - Bobby was the cheater and continued to cheat on Sarah. What I did was talk to him repeatedly, and explained that he needed to tell Sarah before she found out on her own. I did not give him an ultimatum, because I didn't want to take sides. He didn't tell her, but she did find out on her own and they broke up. She eventually forgave me for not telling her and we are still friends; I lost touch with him because I chose her over him after the break up. If I could go back, knowing what I know now, I would have told her when I found out.

Once you have decided on a side, then you can either:

  • Give Sarah an ultimatum to tell Bobby before you see him next. If she does not then tell Bobby that you feel terrible giving him this news but you felt he needed to know. You will be there to support him if he needs it.

  • Tell Sarah that you wont say anything but eventually Bobby will find out and she needs to be prepared for it, and preferably tell him first. You will be there to support her if she needs it.


One thing you might want to consider is to let Bobby know about it anonymously. Assuming the conditions are right (if she doesn't remember telling you about it, or if other people also know about it), they will never know it came from you. For example, drop a piece of paper (not handwritten) explaining what happened, let him decide what he'll do about it. It will not have as much credit as you telling him: an anonymous message is not something most people would blindly trust. But it might make him go after the information and find out about it on his own, or might prompt him to talk to her about it and maybe she'll admit it.

Note that I say this as an alternative to what others already commented, since nobody else proposed this idea. I myself would follow most people's advice of speaking with the friend who admitted the cheating. First I'd have a long talk about it as to why they did that and so on, and try to encourage them to do it too. But I can see how for many people, telling him anonymously might be a better option.

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