I dont have all that much to say right now, but my biggest question about all this has always been this:
Do you NEED to remain in contact with her, or with them?
Absolutely everything you've said about them is negative, and to me at least, just further enforces the idea that a complete, total disconnect... no contact anymore, with no exceptions... would be very beneficial.
Unless there is something you have no choice about... and I specifically mean something like financial dependence, not "they barge in" sort of dependence (because you absolutely can just lock doors and ignore them)... then the only thing actually keeping you in that poisonous connection is yourself.
I mean, even if you were to move, or do something like that, or do whatever, really... it aint gonna help if they are still there to hit you with their general awfulness.
The issue I see here, is that you've said the whole "I'm putting a stop to this now" thing before (or at least, that's what I'm remembering) more than once, but you end up just falling back into rhythm each time. The rhythm sounded out specifically by that negative connection. Why?
I dunno. That's what occurred to me.