Thre truth is that men's biology is such that a normal male always wants sex and thinks about it all the time. Physically, it is an always present urge, that's reality.
For women, its hard to understand that about men because their biology is different.
Case in point, a friend of mine was on a dry spell with his wife and the grandparents were bugging him to give them a grandkid. They were akll driving home from a party and he was feeling frisky. It was like 10:00 at night and he sensed that his wife was getting a we bit tired. The in-laws stopped at 7-11 for something. He went in and got everyone the Starbucks double shot of espresso, in a sneaky attempt to wake his wife up for sex later on. The mother-in law said to him in front of wife "You are trying to get laid arn't you?" He was mortified but responded "You do want a grandkid right???"
Men are more visually stimulated than women. I saw a show that had done a study of sex from the ancient to the modern era on the History Channel. It explained why you have "butt" guys and "chest" guys and why they are the same :)