Welcome to bpdfamily, Floyd76b!

Glad you're here.
I know many people here deal with constant accusations of cheating. I dated a guy once, not BPD, but he was extremely jealous and it was an exhausting experience. I learned fairly soon to do small things like keep him posted on my whereabouts, show him my phone so he could see who was calling etc.
The bigger challenge for me was learning to manage my own emotions when he overreacted to his unfounded fears. Is that part hard for you as well?
Sometimes it helps us if we have an example to think about. Can you share something that's happened that can help reflect what you're experiencing?
Look forward to hearing from you!
pj