I also absorbed something saddening today, in a similar vein. It was the video on this site about BPD recovery. It features 3 recovered pwBPD and whilst filled with hope for others I felt deeply hurt by the fact that it is too late for me now. My turn is over. If and when he ever does the therapy and sees it through it will be someone else who benefits. Heartbreaking. Still, if I in any way helped to point him on that path to future happiness I feel satisfied that my role in his life wasn't for nothing other than to be one of and endless stream of reinforcing abandonments to him.
I feel this all too much as well. A part of me hopes that she gets better. A part of me hopes that my brutal honesty about possible traits she has, abandonment issues, running from fears, etc. will sink in for her and her next relationship will be her last. But a part of me doesn't want that. It makes me sad to think I also lost my chance. It's sad to know, as you, that all it had to take was just a little bit of mutual work and then things could have worked out. But you can lead a horse to water as they say.
It pains me because she is "working on herself" although I do believe she is lining someone else up. But by working on herself she is running from the pain and fears. She is staying in control of her situation. I realize that my life is out of control right now. And I hate to not be in control. But I'm trying to embrace it. Thanks for your comment. Because I am struggling at times with the exact same pain. A part of me regrets being so brutally honest with her after the breakup because I just planted in her a seed where she might succeed with the next one. And I hold my head up high that I never did abandon her like your situation. I continued to help her despite it being against my best wishes or for my mental well being. I hope she can look back and say "Maybe not everyone will leave me" and base it off our relationship.
But that's not me. I won't hold ill will. If I truly loved her I'll be happy for her at the end of the day.
I guess the real sad thing is all the research that suggests that our brains neural connections harden after about age 30. Our personalities kind of become set in stone. It doesn't mean our behaviors can't change. Just look at a recovering alcoholic who gets it at age 50 finally. But who they are, how they respond to stress, how they respond to emotions, etc. kind of is locked in. I guess that makes it very, very difficult for a BPD to change. My ex will be 36 in August. It takes harder work to change the behavior than it would be to work on a relationship. So the future is probably bleak no matter how happy they want the world to think they are.