I can't possibly give all the details here, but those living with someone like this can surely understand.
Hey Longsufferingsue, Welcome! Yes, we do understand and many of us, including me, have been through similar situations in a marriage to a pwBPD. Only those of us who have been in a BPD r/s can really understand the stress you have endured. I admire your courage to stand firm and make a change.
I find myself feeling sorry for him because he is totally alone with no friends or family. And I find myself thinking, as always, that maybe things can be better! BUT I KNOW THAT IS NOT GONNA HAPPEN!
You're right, it's unlikely to happen. In my view, his lack of friends/family is his problem, not yours. You're not responsible for the well being of another adult. Suggest you shift the focus to you, by taking good care of yourself and meeting your needs. Many of us here have been down this road before you, so you are not alone.
LuckyJim