How can I orgasm?

Of course, I have had an orgasm before. I know when I'm about to, I know when I have/ all of that. However, a guy has never been able to make me orgasm without my intervention. My beautiful new boyfriend will go above and beyond to make me orgasm but I just can't! How can I?? He performs oral sex on me and it's amazing and he will stay down there for almost an hour sometimes but I just can't orgasm :( I don't want to have to use my hand for clitoral stimulation or anything. I just want him to be able to make me orgasm and he's not the problem, I am. And I'm not saying that in a pity me way.. I'm saying I know it's me because his sex game is A1 but I just don't know why I can't orgasm! Please help