Can't make him cum

so I recently moved in with my boyfriend and I lost my virginity to him a couple of months ago... I really enjoy having sex with him and he seems to really get into it too but sometimes no matter what I do he just doesn't cum. I feel like it's my fault for not doing it right or something but I don't know. Most of the time he does most of the work and I don't exactly know what I'm doing I just try to do what feels good for me but idk how it feels for him and I'm too shy and awkward to ask him for feedback. I was raised very religious and sex was never something you talked about with anyone so it still feels a bit awkward for me to bring it up but I really want him to enjoy it as much as I do. If you have any advice or suggestions please let me know. Thanks