my boyfriend never cums

I have this problem with my boyfriend. We've been together for about 2 months and he's never came from sex or anything I do. He gets soft inside of me after about 10-15 minuets and it makes me feel horrible. He says he doesn't mind and that it takes him a while to cum. But the last time we had sex he got soft and then about 10 minutes later he just finished himself while we were making out in probably 5 minuets and I felt like an idiot. I don't think I'm unattractive? And this has never happened before I just feel so ugly and sad I can't help it. I really like him and I'm worried I won't be able to please him and he's going to break up with me eventually . Everything is fine right now but I worry that he's going to get tired and end it when I get really attached I don't know how to bring it up either. Has anything like this happened to anyone I'm not sure what I should do anymore.