I would just encourage you to learn as much a s possible about NPD, Liza. Your life and your choices are entirely yours, and making those decisions on a base of solid knowledge is always a good thing.
My AXH should probably have the Dx NPD (he's diagnosed BPD) and from my experience with him, it is very confusing to have a relationship with a person like that. It was almost as if the closer someone got, the less they were human to him and the less their feelings mattered, maybe because they were perceived as being in competition with his own feelings/needs. He would donate large sums of money to Katrina relief while I struggled to put food on the table. He would cry in front of news casts about domestic violence and volunteer for domestic abuse victims while severely punishing his own children for minor infractions and abusing me. It was as if he was unable to put his own actions into the same context as the one he interpreted the rest of the world in. I've worked some with people on the fetal alcohol spectrum and his behaviors are very similar to theirs. I'd be curious to know if the brain functions/damage are similar in those two groups.
I struggled a lot with whether I had the right to leave a person who was sick. I had a lot of compassion for him even long after the love was gone. I think for me, an important change happened when I was able to look at his actions for what they were in isolation from what he *said* he was doing. While his talk was often filled with caring and compassion, his actions did not speak the same language.