Abovethewaves
For years the only way I could have an orgasm was when I used 2 toys at once. One for penetration and one for the clitorius. I could never have an orgasm with any man that I was with. Even with that it could take me over a hour just to have a orgasm, if I had one at all.
I actually just learned how to be able to have an orgasm while having sex with my man. What I did was relaxed more. Stop tensing so much and holding my breathe. Once I did that the emotions zoomed over me and I let them go. What a rush! You should try that. Loosing up when having sex. I always held my breathe and tensed up b/c I thought it felt better,,, boy was I wrong.
That could be the reason why you are not having one or many. You should also try what EEK said. After all thanks to her I finally recieved mine

(thanks again).
There is nothing wrong with you for not having one either. Just need to do some real exploring. Have him feel around inside you to find the spot, once you get that, he'll know where to go from there. Maybe even try while he's doing that (if it doesn't already get you there) to rub your clit. It might even turn him on.