Refusing discussion is actually a form of stonewalling, and stonewalling is also a form of emotional abuse. Ambushing your partner into having a conversation because you've brought the subject up around others is indeed a violation of boundaries, as you've pointed out, but stonewalling is problematic in itself; it's akin to the silent treatment, except for the fact that, instead of just neglecting to speak, the person who is shutting down communication is doing so either by:

- outright saying "I don't want to talk about this" / "I'm done talking about this"

- monologuing/shouting/whining/singing/humming over the sound of the person who is trying to continue an open, emotionally mature and healthy discussion

- trying to make the other person feel guilty or wrong for wanting to discuss said topic together to achieve a healthy resolution

- pivoting to a different topic every single time the issue is raised, so that they can avoid addressing it

- cracking jokes to prevent further (REAL) communication

Just wanted to add that because it felt important. Great list you've provided here! Thank you!