I voted YES, and yes, I do know a few men like this. However, in my experience, most men cheat (but not all), and many women cheat, too. I do believe there are some men who don't cheat. And of those who do cheat, it's not necessarily that they can't be happy with one woman. Some men just are no longer happy with the one they have. That's not an excuse to cheat. They usually fail to communicate to their wives why they're dissatisfied, or fail to communicate it in a way that's effective without offending the wife; likewise, a wife may not be receptive to hearing this, may become defensive, and may not be able to become what her husband wants. Both partners have to be open and receptive, and each has to understand that the other may hurt him/her, because it does hurt for your partner to say s/he's not happy with you anymore. Sometimes it can be fixed, sometimes it can't. Sometimes people grow in different directions. For instance, a husband may want a wife who stays at home and raises the kids, whereas a wife may decide she needs to get out and work. Each partner needs or wants different things. You should never do something that will make you miserable to please another person, but if you can make an adjustment that won't leave you angry or resentful, then you might be able to fix things.

And just so we're clear, I'm NOT saying the female has to be the one to change, or that anyone needs to change (except maybe in the communication department). Both will most likely need to change in some way for things to work out when there's problems, though.