i had this problem myself to ....do alot of foreplay with your partner befor going into intercourse
I can rarley seem to orgasm either, foreplay really does help alot, also if your thinking about it trying to force yourself to you wont, you need to just enjoy it and relax your body and it will come, most women don't orgasm from sex its normally from the stimulation of the clitoris. The more comfortable you are with the person your having sex with helps alot also.
Try other stuff like manual and oral sex. If you can get off that way, have him get you off before you intercourse. Thats what my wife and I do, and sometimes, maybe 1/3 of the time, she has another one during intercourse because she is more relaxed and doesent feel the pressure to climax.