Background
I'm in a happily monogamous relationship. I also am friends with someone I used to date. My friend and I generally void the subject of dating/romance now because it can be a sore subject that stirs up feelings. I hope in time that this restriction will ease up as we adjust to just being friends.
I don't know if my friend is aware of my relationship status. Several months ago I mentioned I was seeing someone but it was only a couple sentences. Similarly, she's only mentioned once having gone on some dates after us.
The situation and goals
Recently she proposed about going out hiking and possibly camping. I'd like to go and my girlfriend is fine with it too. I would however like to avoid a few things:
- I don't want to cheat on my girlfriend.
- I don't really want to rub my relationship in my friend's face. If mentioned at all it should be done delicately and not at length.
- I don't want to reject my friend if she makes any advances, in order to avoid hurting her feelings or thinking it's anything to do with her at all.
- I don't want to imply my friend wants to resume a romantic or sexual relationship as I have no reason to suspect this is more than moderately likely.
To me, this suggests that I need to indicate that I'm not available in some gentle fashion, either preemptively or if an advance is made. I'm not sure which approach is better or how to best do either.
I am open to using the (true) angle that I value our friendship so much that I'd rather not risk it with a fling. But that is probably best used reactively so as not to come across as presumptuous and still leaves open the objection that a serious relationship would be a viable option (which I think it would be, were I single).
To clarify my feelings about a relationship with her in response to answers and comments, I simply mean that I like her far too much as a person to risk the friendship for a casual romance and, hypothetically, would only consider her for friendship or a serious romantic relationship that aimed to be lifelong. For practical reasons, I don't think a lifelong romance is possible here and I don't harbor any hopes of changing that.
The question
In the context of camping together, how do I let her know that I'm romantically unavailable without causing upset?
I'm open to frame challenges that don't involve me avoiding my friend.