Did you not want a reply to this? Forgive me if that's the case. Your words were/are mine. I hope you find peace. I am not healed, but am definitely grateful for the much more peaceful space I find myself in…and I've only arrived there after seeking explanation beyond the "BPD" label. I now have those answers that bring me peace.
You go to bat for someone in their darkest hour. You put every bit of your resources into providing for their needs. In return, they use you, extract every last drop of life from you and when the well runs dry - they self destruct and move on to a new host. Some people are, not because they doty things - they are because they doty things over and over. They do this fully aware and refuse to take the steps necessary to change the behaviors that hurt others. The worst part is their ability to appear as a decent person at first. They keep the mask on long enough to get into your keep, and then the looting begins.