whats wrong with me?

If you are a girl, this is common. Only about 30% of women can reach orgasm from intercourse alone. Try clitoral stimulation while he is inside you or try some new positions that stimulate your G-Spot

I agree with above, woman are less likely to orgasm during sex than men are. Do you masturbate? If you masturbate you are likely to know your body more than those who don't, and then you'll be more likely to know what gets you off. Also, like said above, most woman cannot orgasm unless they have clit stimulation. Have either he or you rub your clit during sex (or get into a position that allows for clit stimulation from your bodies...)

It's a practice thing, don't give up! Just get yourself in the mood and keep trying.