No, this is not a mediccal condition. :-) I'm afraid that what you are experiencing is quite within the normal tracjectory of a maturing relationship. You might want to scan the net for some Sex Statistics. What you will find is that most couples who have been together for a few years do not have sex every day, and mostly only once or twice a week. She is not punishing you, but as always, the best thing for you to do is to make sure that you are both communicating your needs (or lack of them) to each other, and negotiate a solution that suits you both.