A friend of mine (she's deceased now, God rest her soul) used to say a lot, "Men want what they can't have." ;)
People want what they can't have, and if they can't have it readily, that makes it seem more valuable. But I believe men tend to be this way more than women are; it's hard-wired into their brains.
In the last century women shot themselves in the foot with feminism. First, we made ourselves less desirable with our choice of fashions and our unfeminine behavior, and then we began handing sex out casually to anyone who asked, or even men who didn't ask. How can a man treasure, respect, honor, and long for a slut who has been passed around and has more mileage on her than a '67 Chevy? It's my belief that men (good men, anyway) really do want to find some goddess and fall in love with her and give her fidelity. But it's pretty hard for a man to think of her as a goddess to be cherished when she's throwing herself at him.
So do women.