He felt a connection with you, or he wouldn't have decided to be with you.
People with this disease feel
entitled to things, and so they don't decide to spend time with people they don't have any feelings for "just because".
He thought it was love, but if he has a narcissism, issue, they don't know how to love.
So you filled the "hole" in his soul, at least for awhile, because that was what he was looking for.
My XABF with similar issues was interested in looks, intelligence, and youth, so at least I know I have those things going for me. I suppose I can take it as a compliment.
I'd suggest figuring out his "tastes" if you can - the things he seems to notice about you or others - and then just take it as a compliment that you have those qualities.