I would love some insight on this type of situation and what I've talked about here. But more importantly, besides the positive reassurance from other victims of abusive relationships, I want to say to anyone still dealing with this, DO NOT! GET OUT! YOU CAN'T HELP SOMEONE LIKE THIS AND IT'S NOT YOUR JOB!
This indicates to me that you may have posted this in the wrong board. People here are trying to improve the relationships with their loved ones that suffer from BPD.
I am sorry to hear that you have had such a hard time with all of this. You seem to have had a really negative experience. The difficult part about BPD is that despite it being a firm diagnosis that has a list of symptoms, it affects everybody differently. Additionally, people that suffer from this disease can have widely varying views on therapy and how helpful it is for them.
My wife went to therapy for five years before we met. I see that as the biggest reason why she has been able to control her symptoms as well as she has throughout our entire relationship. She has made mistakes and so have I. We are separated right now.
However, both of us have been accepting responsibility for our actions. We have both been apologizing. She has been meeting a few of my needs when I have asked her to meet them. She has been going to therapy again. She is making more good choices to pull herself out of this hole that she helped dig for herself.
In short, out of the three years we have been together, the last two months are the only consistently rough times that we have had. This means that more than 94% of our relationship has been generally positive. Have these past two months been gut wrenching and difficult? Of course, but there are a lot of things that I also did to contribute to the situation. That doesn't excuse her actions, but it makes it easier to forgive. It seems like we could get back together by the end of this month. Maybe not.
Even if we don't get back together, I feel confident in saying that we would divorce on good terms. Whether or not we get back together really hinges on both of us figuring out our boundaries and whether or not we can respect them. Even if we realize that we wouldn't ultimately be a good fit, we still love each other and would be willing to let go.
All BPD relationships have difficult moments, but in reality, all relationships do too. Untreated BPD is definitely hard. I won't try to pretend like it isn't. However, not all people diagnosed with BPD refuse treatment and there are people that are able to improve and live significantly better lives.