Sex struggles?

I've been with my boyfriend for 2 years and the relationship is great, we are 18 years old and a few months ago we had sex for the first time, although we were doing everything but sex for like a year and a half before this so we are pretty comfortable with each other in all aspects.

The one thing that I'm unsure about is that during a situation like oral he says he doesn't feel like he could finish from it, same goes for sex. He promises he is enjoying it, and I can tell that he is, but a finish during sex seems unlikely and a finish from a handjob or oral has only happened a handful of times, not from lack of trying. We still enjoy the intimacy of sex regardless of wether he finishes or not but I think it would be a good experience for both of us if he were able to finish with me, as I want him to enjoy it as much as I do. He says he gets all the pleasure from oral and handjobs but doesn't quite feel like he could finish.

We've talked about it, he says that he isn't too nervous to finish and he is definatly enjoying it. Long conversation short we think that his body is possibly too used to the way he does it himself, he can make himself finish in as little as 2 mins but during foreplay/sex it just keeps going and going until we get too tired. He thinks that having someone else try to finish him isn't the same as how he does it and therefor more difficult. He tried finishing himself less and it hasn't really changed much. We have tried different positions with sex, done a lot of experimenting and the final verdict is that despite feeling a lot of pleasure, he doesn't get that feeling that he could finish. I still love him regardless and we still continue to create intimacy but I would like some tips for anything to do to maybe bring him closer to a finish?