Cumming

I have some sort of a problem it takes me so long to get off like most of the time. I enjoy sex it feels amazing and I do get into it . sometimes I do feel like cumming but just doesn't happen. Or sometimes I wouldn't even feel my dick or when we have sex I would lose a boner sometimes. I don't really know what going on only had sex with one girl first time we had sex I didn't cum went at it for hour and a half. I have masturbated a lot before we did it but now I don't do it as often as I used to.