Hi WoundedLove-
And welcome! I'm sorry you're in the middle of that, it is very painful, frustrating and confusing, although it's not rare around here, we understand.
Have you read much about the disorder? There's a lot of great information out there, and the best thing you can do is focus on learning
why borderlines do what they do and what the tools are for us folks in relationships with a borderline; that can alleviate the confusion a good deal, although the behaviors of your partner are what they are, and you can learn tools to not only tolerate that but make the relationship better.
To start, here are a few good articles that might help:
https://bpdfamily.com/portfolio-save-relationshipAnd also, read a lot and post a lot here, you'll be talking with people who understand because we've been there, and just talking is very helpful. Take care of you!