To the OP I won't pretend to know of that which you speak. I have BPD not NPD and I really apologize for any derailing my post may cause. I just couldn't hold my bloody tongue any longer

Firstly, you don't know if he has a personality disorder, he hasn't gone for any help, and secondly I would like to share something with you.

I too dated an abusive a.s.s.hole for years, I didn't bother diagnosing him with anything though. I think a.s.s.hole is fitting enough label I found myself obsessively trying to save my relationship too, mind you I was trying alone too, just like you. He couldn't care less, he thought he was the bees knees and that he owned my a.s.s. Never put in any effort beyond whispering sweet nothings and making empty promises. I did all the leg work, why? Because I WAS UNHAPPY, ME. He did nothing to assist because for him everything was a okay

Anyway, I left because one day the abuse escalated dramatically. Verbal abuse and threats switched to me being beaten to a pulp.

#Helpful hint 23, bruised ribs are no fun, beware the boot!

So I left, it wasn't easy, not at all. It was like going through withdrawls... I constantly second guessed myself, my decision and wondered what I could have done differently to fix us. What a chop I was!
I wonder if I suffered from temporary retardation back then???

Then 1 day I had an epiphany, which is what this longwinded post's point is:

"Don't fix it if it ain't broke"

From your posts, your relationship is what it is what it is, and your bf is who he is who he is.
There's no changing him, or the nature of your relationship. So either you accept being treated like shyt, or accept you deserve better and move on.