MsLady, why not see a doctor with him to confirm your suspicions of BPD? You are not qualified to either diagnose nor start treating an illness that you don't even know exists.

Why are you trying to explain away his behaviors by means of diagnosing him as having a mental illness that you can then say is causing these behaviors? You're spending a lot of time and energy on things you're not qualified to determine.

If you really suspect this, then see a doctor with him and get a real diagnosis. Get him an MRI and talk to doctors. You're doing a lot of speculation without medical consultation and tests.

Perhaps it's too hard to face the fact that he is abusive. Maybe that's too hard to stomach for you, and you'd prefer to think his behavior comes from mental illness or brain damage. I really do not know. What's so wrong with determining that he's abusive towards you, and that perhaps you need to leave him because of that?