It seems like orgasms are akin to an addictive drug-the more you get the more you want! I'm afraid I don't have much of an answer except maybe there is nothing wrong with you. After you conceive, you may have a time when you want it less.
As long as it doesn't interfere or cause problems in other areas of your life, you're probably not in too much trouble. If it persists, I would suggest discussing it with your OB/GYN.