My AH also was diagnosed with borderline personality disorder many years ago and I too often forget that.
One of the things that kept me stuck was that fleeting glimpse now and again of the wonderful man AH could be. Only, he couldn't keep it going for any length of time and his true character came out. The "wonderful" could have all been an act just to manipulate me, to get what he wanted out of me. Typical behavior for someone with BPD.
I really need to have relationships with people that don't need "figuring out".
Continued peace and happiness, Zoso!