Did something happen to my boyfriend sexually?

I am wondering if there is something wrong with my boyfriend. He is an older guy at 38 and sex is a little off with him. I enjoy sex and he doesn’t seem to follow the norm. at all in bed, he seems to think I am being perverted most of the time. He doesn’t like a lot of things and we have sex only about once a week; he doesn’t seem interested in sex really. When we do have sex its always in the same place and the same position. I usually have to innitiate the fun if we get to have any, I am the one that wants to try this or that. He never wants to try something new or just play. I have tried lingerie but for the most part it goes unnoticed or walking around him nude and still not much of a notice unless he is in the mood. I have mentioned pornography and still uninterested, he actually says what’s the point. We actually ran into something on tv once and he had no interest in it at all. He does not look up sex on the internet from what I can tell. I have tried to talk dirty to him and he doesn’t participate. He still has a problem for the most part about being nude in front of me and trys to hide himself and we have been dating for 2 years. If I touch him when he is not in the mood I seem to bother him, and I am just playing with him (no pun intended). If I flirt with him again I am being perverted. He thinks masterbation is perverted. He seems to make a few comments that could be considered as sexual but it’s brief. He doesn’t go out and about so I am not too worried about an affair but the way he is seems unusual. He seems to need to brag about what all he has done in his past but from what I can see, I find it very hard to believe. I have asked if I satisfy him and he says yes and of course he would say that but I can’t seem to reach him with sex. I have asked a few people around about his behavior, most are confused and two people have mentioned maybe he was abused. I know better than to ask, but how can I tell if there was something from his childhood that holds him back as an adult? If it’s not sexual abuse as a child is there something maybe he is into but embarrassed to tell me? I am truly confused.