Why don't I attain orgasm during intercourse?

I am 26 years old and got married 1.5 years ago. While having sex, I get satisfied only by rubbing and not through intercourse unlike my husband. I attain orgasm after a lot of effort and vigorous rubbing. Moreover, I don't get aroused easily. I always try to avoid intercourse. I do it just for my husband's satisfaction. I am very worried about our marriage as it is not very old. I have never enjoyed intercourse even for a single day in my married life. Now we are planning for a child. I don't know what to do. How can I enjoy sex instead of rubbing?