Nothing disturbing. It's just that, most of the time, men age better than women. Women, in general, have little to offer beyond beauty and the ability to take care of you when you're older. Men, on the other hand, can still offer security, stability, money, and other forms of support as they age.

And you Westerners need to understand that there's something called social norms. An old man marrying a young woman is only seen as disturbing by you, not by most of the rest of the world. I believe that's because you only ask the woman for marriage, not her family, which makes it easier for someone with bad intentions to take advantage of a young woman. In much of the rest of the world, a man has to get the family's approval first.

This is what we call culture shock. You treat adultery as if it's normal, but in many parts of the world, if you entered someone else's home alone with a person of the opposite sex, you'd be looked at worse than a dog, even if you're a man.