please help!

My boyfriend and I are young and he is having a very hard time ejaculating these past few weeks, usually it's very quick but now he can't even finish at all and he's so frustrated and doesn't know what's wrong with him and has no one he can talk to about this. He says he hasn't masturbated in a pretty long time, could that be why? I just want to know what's going on becuase I'm very worried! He doesn't even want to have sex anymore because it frustrates him so much that he can't cum. He has no problem getting hard, it's just reaching orgasm. Please please help, don't ignore!