I feel like it’s me

I’ve been with my guy for 3 months. We have sex on the weekends when I’m not in college. He always puts my needs first and makes sure I finish.

Buuuut

He doesn’t cum....like at all.

We go at it for an hour or two and still nothing. When I try to change positions because I’m cramping in one, he gets soft.

He’s going to try to not masturbate for a month and see if that works but my self esteem is getting the better of me. I give him head for awhile until my jaw starts cramping. He moans and twitches so I know I’m doing fairly well.

What should I do?!?