Hello, Paper kite! Welcome!

I'd like to join
Kc2419 in saying that you're not alone. What you wrote is very familiar to me and to many other members here. Like you, I was berated and blamed and verbally attacked for all kinds of things and told it was my fault. For a while, I believed it. Then, something clicked and I finally realized it wasn't me (or wasn't all me -- there were things I was doing that were making the situation worse).
It's so frustrating and painful, isn't it? And it's difficult for a non (someone without BPD) to wrap one's head around.
Have you read the book Stop Walking on Eggshells? It's an incredibly valuable book that many of us here have read. It really explains the BPD mindset, where it comes from, how it manifests itself. That book is what led me (and many others) here.
I know you're in a very difficult situation. Believe me. I've been there. But the people here can help. We have a lot of tools and tips and experience to share. While it seems hopeless at times, there are things you can do that can possibly improve your relationship. It's worked for me.
There are a lot of things that I've done that really helped me cope. If you'd like, we can share some of that with you. Sometimes, describing one recent incident (how it started, what the pwBPD said/did, how you responded) can be a big help to us in figuring out how to help you.
Keep posting!