Hi,
Before I responded, I googled bpd just to refresh my memory. I lived for 10 years in a relationship with someone exactly like this. Marriage, two kids. It was unbelieveably difficult. I have never completely "gotten over it." One good thing about it: it makes a "normal" relationship -- one filled with trust and consistency and good humor -- seem so very precious.
Leaving was the hardest thing I've ever done. To this day, I think of it as harder than labor. The guilt was almost unbearable. But I did it. It was the best thing I've ever done. He survived. I survived. The kids survived. He lives just a few blocks from us and has done his best to be the best dad he can be. He is very strange, however, or not, depending on the day.
I cannot tell if he has gotten "better." I never know when I see him if he will be friendly and appropriate, or will barely speak to me. I have learned to be light and friendly and be MYSELF and not be scared of him. This has been the gift of distance. In the last two weeks, we have gone out to eat twice (both kids' birthdays) and it was fine. Strange, of course, but fine.
The main thing I learned thru this experience was that I could not make him happy, no matter how hard I tried. It was not in my power. Al-Anon helped me to see this. The most frustrating part of being involved with a person like this is that they refuse to admit they have a problem. The problem is everyone else -- the mean guy at the job site, his mom, his brother, some guy who looked at him funny, the bully from his childhood. I thought I could fix him, love him enough, but I could not and when I felt my spirit being damaged, and when there were too many tables flipped over and toasters flying across the room, and scared-looking children, I got out. A trusted therapist saw me thru the transition.
Though my kids were hurt by the divorce, they are now old enough to see for themselves that their dad is "different". I think they understand why I had to leave. They love him tho, and he loves them. He has been a good father.
I cannot believe how much happier I am.
I wish you well on this journey. Feel free to pm me at any time.