I lend a patient ear to her outpourings without invalidating her feelings or accepting blame for a few minutes to let her vent, and then I carefully try to disengage by leaving the room or situation under some pretext. The issue is that she calls this out as avoidant behavior and escapism and consequently her conflict increases with the belief that I am not trying to address her emotions.
It seems the only thing that will calm her is sitting near her and listening to the insults, frustrations, name calling for hours on end until she tires out. Am I missing something or doing something wrong - what is the appropriate way to disengage in such situations in a manner that when we return back the pwBPD has calmed and moved on from the splitting or their peak feelings?
When you start a new boundary, there
will be pushback. We refer to it as an
extinction burst. Obviously the pushback can be quite extreme due to the BPD traits, moods and perceptions. In your case, it is manipulative with her blaming that you don't care. You know it's not true but by staying and weathering the storm you're reinforcing her poor behavior. If she can have self control in public scenarios, then it's not unreasonable for her to limit her actions in private times too. (Sadly, she won't see it that way, especially once she's worked herself up into a frenzy.)
You can listen... until it starts becoming a Blamefest. That's when a Boundary should kick in, such as calling a time out, a breather or exiting to let the other reset, otherwise you remaining there as a suffering audience, even a Whipping Boy*, becomes
enabling.
* Whipping Boy is a flashback to olden times where, as the story goes, a poor kid would get the punishment due an entitled kid.
Your children are older. If they're there too, they could easily decide to not be spouse's backup audience, perhaps even go with you if they get hounded to meantime have some peace.
