I'm going to (partially) play the devil's advocate here. But before I do, let me make a few things clear:
- Your boyfriend is an adult (I assume) and is responsible for his actions and their consequences.
- Relationships only work when both partners are in it together. If one of them wants out, the other doesn't get to veto that. Emotional blackmail does not save relationships, it kills relationships.
- None of what I say, if correct, obligates you (morally or otherwise) to suffer your boyfriend's behavior. When you draw the line, that is where the line gets drawn.
- You are within your rights to outright not accept this behavior, regardless of potential mitigating circumstances.
- Mitigating circumstances are invalidated when they are intentionally gamed. Gaming the system is outright manipulation. It's nigh impossible to ascertain whether something is genuine or merely acted as genuine. This can only become clear when seeing someone's behavior over an extended period, which doesn't translate over your description.
- I am not making any judgment nor definitive statements. I am only pointing out possible explanations and mitigating circumstances.
- I might slightly rephrase what you said, because I'm accounting for your description being influenced by your perception. This is not done to dismiss or invalidate your experiences or observations, but rather trying to shed a different point of view on the events.
- My answer draws (and illustrates, and fills in some blanks) from personal experiences. This is a matter of example to prove the point that there can be less-than-obvious connections between two seemingly unrelated events.
Playing the devil's advocate.
Based on your description of events, it is not wrong to label the behavior as abusive. Whether the behavior can be labeled as willfully abusive, however, is not as clear cut; and this is what I'm trying to focus on.
Reading between the lines here, there are certain flags about the behavior that make me identify with personal experiences. Even if correct, that doesn't absolve your boyfriend's behavior (as it doesn't absolve mine either), but the point of mentioning this is to show give you an insight from the other side, to understand why the reaction (possibly) emerges the way that it does.
In short, I was raised by a strongly narcissistic and dominant father. He was dismissive of anything that he didn't agree with; frequently told me that my experiences were not real, lies, or willful slander; prevented me from speaking in cases where I he know I could disprove his statements (often resorting to filibustering); never admitted mistakes; and resorted to random punishment, bullying and violent behavior when I countered his other tactics.
He said it was because I spoke over him when I spoke regarding the dog and that this made him angry.
This is a massive trigger for me. Having been talked over my entire life and having anything I say dismissed as meaningless has rendered me easily irritable when what I say is interrupted or ignored.
This is seemingly confirmed when you said:
He expresses how I don't care
He seems to be sensitive to people ignoring him and how this means that they don't care for him.
Notice how he immediately equates being talked over to being un(der)appreciated. That seems like a clear indication that in the past he has been talked over/ignored by people who showed affection for him (or interest in him) less than he needed/wanted/expected them to.
Without trying to blame you, I do want to point out your statement:
but to my mind the more important topic to everyone is the state of our dog's health.
If this is how you phrased it, you have basically informed him of your decision that your topic is more important than his. I doubt that that's what you outright meant; but your phrasing does leave it open for that interpretation.
If he's sensitive to being dismissed, he's also going to be prone to favor the interpretation that seemingly dismisses him. I have similar reflexes that I have to actively counter whenever I feel them pop up.
In response, he took the remaining chocolate from my desk and threw it out into the trash, stating "If I can't have it, you can't either."
I mentioned that my father would resort to random punishments when his other tactics failed.
To my regret, I've ended up applying similar "punishments" to my SO when she seemed to dismiss me or otherwise treat my like my father did. And it seems your boyfriend has a similar response.
A simple example of how this can escalate, I'll use an personal example:
- I'm listening to music, relatively loudly (but was allowed since I had a floor to myself)
- My father enters the room, informs me that he's working next door and "either turn down the music, or turn it off".
- As I'm at the end of my playlist, and leaving home in a few minutes anyway, I turn the music off. I'm not upset about it.
- My father storms back in, red faced, screaming at me for punishing him. How childish I am for turning down the music when he would've wanted some background music while he worked.
- I reply that he told me to either turn it down or off. He could've asked me to just turn it down.
- He denies that he ever said that, and threatens me (without specifying) that I shouldn't lie about things he does.
- I said that I would've happily queued some more music or given him the computer after I left.
- He interupts me, takes my ice skates (which I needed to go out), breaks them, and grounds me for insubordination.
It didn't happen in this case, but had I then escalated due to him breaking my ice skates (or in any other way refused to yield after being punished), he wouldn've resorted to outright violence.
Looking back on in now, fifteen years down the line, I see that his reaction displays a victimization that he then subjected me to: he felt randomly punished, I did not agree with his version of events (to him, that is dismissing him), and he therefore enacts a random punishment on me.
This seems very similar to your boyfriend's reaction. And, if your boyfriend has indeed suffered through similar abuse, it makes sense why he'd respond this way.
You (inadvertently) end up wearing the mask of his abuser, and therefore he retaliates in a way that befits how the abuser mistreated him. He's responding to the abuser, not you, and his strong emotions make him forget that he's dealing with you, not his abuser.
So now what?
This isn't as clear cut. If you do not accept his behavior, and do not consider past abuse he was victim as a justifiable mitigating circumstance, then you should consider either drawing a strong line (ultimatum), or consider ending the relationship.
If you do want to work through this, the first step is to have him confirm that his behavior is a kneejerk response based on his past.
Important
It is possible that he doesn't (yet) acknowledge past abuse, or sees it differently. Until I was 25, I was somehow unaware of my father's unacceptable behavior. It took a friend to repeatedly explain why certain past events were abusive and not just "me being a difficult teen", before I started realizing it myself.
If it is the case, then the next step is to get him to acknowledge that his response, while feeling justified to his point of view, is not something you've deserved. You are not his abuser, even if you sometimes end up touching on a sensitive topic.
This is not easy to work through. Many people would discard abuse victims as "too broken to date/love" (personal experience). In a way, he may always be sensitive to those issues.
But if my SO hadn't stuck with me through it, I wouldn't have been able to identify my behavioral issues and work at improving them.
This is your choice.
Assuming you work through it with him, this will be a gradual process. He'll be sensitive to being pushed around, and therefore won't accept you pushing him towards a more healthy behavior. It needs to be voluntary.
- Focus on explaining your perception, without making statements as to what he did or said. Don't dismiss him when he brings up his side. Acknowledge them and explicitly (tell him that you're doing it) pull focus to your experience.
- Make a clear distinction between him and his behavior. Make it clear that you're addressing the behavior, not him personally. If he feels targeted, he'll get defensive, and you'd be surprised how strong his defenses can be.
- Acknowledge that his interpretation is a possible explanation of what you said, but point out that it's not the only possible explanation.
- Ask him to identify what triggers the emotional outburst (I'm pretty sure it's being dismissed; but the point of the question is to get him to find the answer himself. He needs to self-reflect). If he knows what triggers it, he can start intervening on his own behalf.
This subject matter is deep and wide. I suggest reaching out to online communities such as /r/raisedbynarcissists.
- Narcissistic behavior (and the learned behavior by the victims) is very recognizable. If you read other people's stories, you'll notice that it often mirrors experiences you've had (or that sound completely in character for your case). I see a lot if similarities between the example I wrote and your story, for example. It's the same story but with different words.
- It may help him to read through some posts there. The community strongly focuses on explaining why certain things that you're raised to think are normal are most definitely not normal. Having some random internet stranger tell me something that should've been obvious was actually massively helpful. Often, you don't realize that the (victimized) lesson you learned as a child is wrong, and you never question it until someone points out the obvious flaw in your thinking. For over a decade, I considered my father's violence to be proof of what a problem child I was; even though I was able to argue the opposite point when supporting someone who went through domestic abuse. After a while, you start tricking yourself into believing the abuser's truth.
- There are many links in the sidebar to resources that help you identify narcissistic behavior, and how to cope with it .