I have this problem. Despite how experienced or how skilled my partner may be, i can never cum. Don't get me wrong, it is very pleasurable to me and it defintely feels great i can just never get over the top during actual sex. While masturbating I can cum through clitoral stimulation but never through g spot stimulation. Also I never ever have cum. Even when i have an orgasm there is no cum. Ive gotten very wet but havent cummed. Whats the problem!
You're sensitivity is just elsewhere in your body. There are plenty of ways to work around it with a partner. You just have to communicate as you would in any relationship and tell them what works for you. It'll be awkward at first since it might be new for both of you, but it's not hopeless.
If you are having male-to-female intercourse than this is rather common. Only 25% of women can orgasm during penetrative sex. Secondly, female ejaculation is extremely rare- only a small percentage of women are "squirters".