Hi and welcome! There are MANY people on this site who know just how draining living with a BPD is. Even just talking with a BPD can be very difficult. But it can get easier!
I would suggest reading up about Validation. This is a conversation skill that should make conversations less likely to explode. The key is to realise that when he talks, you need to be listening to what he FEELS, not what he SAYS (and ignore the CAUSE of what he feels, just focus on what he feels now). Read it here:
https://bpdfamily.com/message_board/index.php?board=36.0The best way to learn is through specific examples. Post some conversations here and we can guide you through the mess.
It can get better! Just be patient... .