Virgin problem

I'm 18 years old and I am currently in a relationship with my boyfriend whom is still a virgin, we have been dating for a few months now and I was the first person for him to do anything sexually with although every time it starts to get sexual he hesitates and sort of stops, it's getting very frustrating and I'm not sure if he's just nervous or if he doesn't trust me enough for him to lose his virginty to.. Anyone any advice?