HI Kronos,
Welcome! You've found a great place for support and help. I know what it's like to get reactionary to my pwBPD. It's easy to do after a period of them pressing your buttons. It sounds like you do see that you could change how you respond, but you're just having difficulty figuring out how. Could you share an example of how a conversation might start and then how it goes downhill?
We have 2 really great communication skills that I think might help you. They are:
1.
Validate2.
Don't JADEBoth of these have completely changed the way my conversations with my H go. Validate doesn't mean you have to agree with your pwBPD, but you empathize with how they feel. Don't JADE stops you from trying to justify, apologize, defend, or explain things to your pwBPD, which leads them to think you are being invalidating.