Sex newbie needs some help

Okay so I recently lost my virginity to this guy that I really like and neither of us came this first time, but then he figured out how to make me cum. Here’s the problem though, we’ve had sex on three separate occasions, multiple times on those occasions and he’s never cum. I’ve asked him about it and he said it’s just hard for him to cum sometimes, like when we’re having sex he’s right on the edge, but can’t quite go over. Is there something I can do to help?? I’m really nervous that the sexual chemistry isn’t what I think it is ((I think it’s pretty damn great)) or maybe he just doesn’t think I’m attractive or if I’m just bad at sex? I could use some advice on this ladies.