To clarify, learning about the disorder didn't erase the anguish, it erased the confusion.
Yes, confusion. Sorry for that, I guess I associated the two in my mind. About NPD and BPD, I agree with everything you say. That's why I couldn't remain in my relationship because how I felt about the behaviours I received - regardless of their reasons- far exceeded my boundaries. I know where taking that risk takes me from a prior relationship. I didn't want to be exposed to those behaviours and neither did I want to show behaviours that would damage my balance within myself and make me dislike myself in the long run. This is a dance for two.
Yep, I had weak boundaries going into the relationship, in fact if they were stronger the relationship never would have started. And it takes what it takes, and one of the gifts of the relationship was to smack me in the face with the consequences of weak boundaries, sometimes the lesson needs to be delivered with a club to get through to me, but I got it this time. Moving forward... .