You'll find a lot of support here. Living with a BPD partner can feel extremely lonely, but the folks here are just wonderful. I'm pretty new to the site, too. It's a huge relief to just know that we aren't alone.
the damage in some ways has been done. I feel beat down and burnt out and depressed. When I try to talk to her about how I feel she twists it around to be about how she feels - which is angry
I know exactly what you're talking about. Anybody would be exhausted dealing with what you've dealt with, and knowing she's getting help for herself makes no difference in the things that she's done in the past. Things have recently been better in my own relationship, and I feel guilty for hanging onto all the abuse that has happened in the past. I carry a lot of baggage that my SO doesn't even comprehend, and it leaves me pretty bitter sometimes. I certainly can't talk to her about it because she's incapable of understanding how her behavior hurts other people, and she gets angry and instantly defensive. It's just the way she is.
I'm seeing a counselor, myself. I resisted for a long time (I shouldn't have to see a counselor just to deal with a relationship!), but it's part of my radical acceptance practice. Fact is, I feel just like you do: beat down, burnt out, and depressed. And I have nobody to talk to. Seeing a counselor to help manage my own emotions seems like a good step in the right direction toward taking care of myself.