Hello, BPK and

What you describe it does sound like BPD, but we are not qualified here to diagnose her, it could help if she had an official diagnosis and all the focus of her treatment would be more to the point. It is a blessing that she is open to treatment, but I know it is discouraging for both of you when it is not enough.
As you have guessed, it is very important that you take care of yourself. Not a small part of that is being brave enough to ask for help, and just being able to talk and express your frustrations and being understood, it goes a long way. Partners, we also disregulate our emotions and reactions when we are very frustrated, tired, and we feel the situation is not fair to us (undeserved hate). So it is important that we find ways to soothe our emotional level, and be mindful enough to face the challenges without making things worse for ourselfs and for the couple.
You seem very aware of your reality and willing to work in your family, so I think you'll benefit a lot from learning bit by bit all the tools explained in this website. When thinks start to make sense, new paths open to well being.
Take care.