Hi Peace95,
Welcome and hello

I'm sorry for what brings you here, and glad you found the site.
I share a lot with your story, including being divorced from my son's absent father (also BPD).
Does your son live close by? How long has it been since he pushed you away?
There are many ways that BPD can present, and you mention he is textbook. By that, do you mean SI and cutting? Does he abuse substances?
Being pushed away is very painful. What tends to happen when loved ones reach out to him?