Yes. It is common for pwBPD to try to find validation from other sources instead of working on relationship difficulties. That doesn’t mean he won’t return. This is very difficult for you.

Thanks so much! I’m at least relieved to hear it is normal, even though it still hurts. He says that he didn’t start talking to anyone until we were broken up or “on a break” or whatever we were. I don’t really think I believe that, but it doesn’t matter much anymore so I’m trying not to get too anxious about it.
I’m just trying not to concern myself or drive myself crazy thinking about what he’s doing or who he could be with. I don’t expect him to come back anytime soon, so what he does now is none of my business. We’ll see if he comes back in the future..
Thanks again for your help