I am 30 yr old female, I can't have an orgasm while making love to my boyfriend?!

I am 30 yr old female, I can't have an orgasm while making love to my boyfriend? What's going on?

I have had many sexual partners, but have only been able to reach orgasm with 2 ever through intercourse, I can orgasm easily from oral sex, but don't understand why I can't when we make love. I get very aroused & highly enjoy sex with him, but don't understand why I can't have an orgasm. He thinks he is doing something wrong, but I don't. I don't want my inability to climax to have a negative effect on our relationship, what can I do? Is there something wrong with me? We have tried several different positions, and I've come very close to climax. I worry now when we have sex because if I don't have an orgasm, he feels bad about it, I would like to have orgasms too, but even though I haven't I still am turned on and want to make love to him as much as possible...any advice?

I may not be a great actress but I've become the greatest at screen orgasms. Ten seconds of heavy breathing, roll your head from side to side, simulate a slight asthma attack and die a little