"at its core abusive behavior is about not being able to tolerate or manage your own emotions and believing that people besides you are ultimately responsible for this" -> I think there is also a counterpart/corollary to this which is "not being able to tolerate or manage your own emotional responses to other people, and so trying to manage those people's actions and emotions into an arrangement that does not cause you distress" - rather than pushing responsibility onto others, it's denying them agency, because anything they try to do or say is subsumed into your meta-narrative of the situation.
Which is maybe distinction without difference, because it plays out the same, more or less. Just, rather than externalizing an emotional response that scolds people around you when they don't act the way you want, it's more... very nicely and kindly explaining to people what they actually think and feel, and why they acted in that way and what it means. Very heartfelt and earnest emotional processing conversations where what happened in what order and who felt what and why are rehashed into mush and reshaped.
In some cases, I think this can result from a failed attempt to mitigate the first type of response. Someone who is aware that they need to learn to analyze their own motivations and how their emotions shape their actions, and that they need to learn how to manage themself to avoid setting themself up to be hurt - but, whose sense-of-self boundary is bad enough that they also apply these tactics to everyone around them in a continuum with themself. Analyzing other people's actions as if your own emotional state was a universal baseline, a fundamental truth which they are at all times aware of. As if they were extensions of you. And trying to manage them into place in your emotional schema, like unruly twitchy limbs.
To have a usable model of someone else's emotional state, you MUST acknowledge that you could be wrong about it. If your model of them operates on the assumption that you know what they really feel, you're modeling them as an extension of you.
For me, one of the worst parts of untangling this was relearning that it IS normal for someone's understanding of a situation to change over time - as their emotional state changes, their intepretation of what happened will also shift. As long as someone is not expecting you to instantly and seamlessly comply with their reinterpretation, this is actually... fine. I had learned such a fear response to someone's interpretation shifting that I felt a need to create a stable understanding of What Actually Happened And Why, and to have that be untouchable. Unfortunately... that's exactly how this behavior propagates forward. My stable understanding wasn't actually intrinsically more stable than anyone else's, and now I was the one trying to force people to comply with the conceit that it was - that is, to edit their understanding seamlessly to match changes in mine that I was willfully unaware of.
To have an understanding of the world that feels steady and reliable, you have to be able to accommodate a bit of a shift back and forth, in your perspective and that of others. It's scary trying to build this when you're used to people completely upending the world on you. But it is possible to build trust that people will shift back and forth but maintain a steady enough overall position that you can work with it. And with an understanding like this, you're able to recognize when someone's perspective is swinging hard due to a strong emotion, and to integrate that with your existing understanding of them, rather than having it totally destroy what you think you know. And, you're able to shift your understanding of them if you find out it's wrong, without feeling like that destabilizes your entire relationship with them, because you didn't build the relationship on the hard assumption of them being exactly a specific type of way.
