How to make oral better for him?

Alright, so I have a problem. The first time my bf and I tried oral, he was super enthusiastic about it. But after going down on me, he told me he was really uncomfortable and hasn't wanted to try it since. It's been like a year, and while I get that he's not comfortable doing it, I'm starting to feel a little left out and honestly a little offended. I keep everything clean and trimmed down there, I'm not sure what else I can be doing. 
I'm trying to think of ways to make the experience better for both of us instead of just getting mad at him for not wanting to eat me out. Anybody have this problem, or any advice? I've thought about maybe suggesting using a dental dam.