My friends with benefits has been acting jealous and acting nicer to me since I told him I started dating, but has told me that he doesn't date at all?

like he has said that I'm the best he's ever had and asked why I want to keep him around. he wanted to see a picture of the guys I was dating. but he also said that girls he hooks up with always catch feelings and he has to tell them that he doesn't date at all?