Thanks for the helpful comments, I think I've worked it out.
All girls are different; and if he's only been with you, how would he really know what other girls are like?
If you want to make this happen, you may need to get over feeling wierd about stimulating yourself. Try different positions, some will give you much easier access with your hand while he's inside you.
He rubs it for me, I feel weird doing it myself. I havent had many problems with this before but recently I just don't seem to be abke too, no matter how close I get, and it effects him more then me. Once he got upset and said that no other girls are that hard (even though I'm the only girl he's been with).
Do you rub your clit directly with your fingers while having sex with him? The majority of girls find it hard, if not impossible, to reach orgasm without direct clitoral stimulation of some sort.
Start by doing it in front of him, have him watch. Then next time have him do exactly what you did and go from there. You know your body and are the best teacher for someone else.