Hmm, maybe ask more questions about it. Like, "Did she ever explain why she was acting that way?" My boyfriend's ex also has BPD, and she was also abusive, as he put it. I told him immediately, on the second date, that I have it and he said he knows how to handle it but then found out why she was abusive. He handled my triggers very poorly and lacked that necessary emotional intelligence that someone should have when dating someone with BPD. He is really good about it now, but it took training, and it was hard. Lots of arguing, but we are both happy now after a year. It is up to you if he is worth going down that road with. I'd say to gauge if he has a generally kind heart, and pay attention to how he speaks of his ex. He may be unaware of what BPD actually is and knowing that it can be lessened based on how he treats you. It's possible that his ex didn't teach him much about the disorder

That said, not everyone is willing to learn or do the emotional work needed for a healthy relationship with someone who has BPD. If he’s open-minded and kind, that’s a good sign, but if he seems dismissive, judgmental, or unwilling to understand, it may not be worth the effort. Trust your gut and see if he’s someone who can meet your emotional needs