I don't think this is true. There are all types of men. Like there are woman.
Of course it's nice to get a complement. Me and my gf care about our body and workout to look better. That's also noticed by others around us. I even don't notice half of the time that a girl is flirting. But my gf notice it and tells me. This doesn't mean someone gone cheat.
We age and it will happen that you get attracted to a other person who is younger or better looking. But it's up to you what you do with it.
Millions and millions of men never ever cheat. Primary reason, No Smoking Hot Chicks are hitting in them. The average guy is shy and not even looking around. The hot chick isn't look'n for Mr. Average.
The Alpha Male is usually look'n to hook up with whatever he can, Hot or Not. Sure some women are pigs as well, but women from an early age learn to fend off boys/men who only want to get in their pants.
Seriously, sure women flirt, it's a way of determining if the guy is a player or maybe a really good guy/keeper. His response tells the story.
Men already in a relationship cheat because the gal they are with really isn't "the one". They love being in the relationship but will still hit on anything they can. Even telling others they "love" their gf.
Problem is they have no idea of what real love is, they love the idea or concept of being in love and in a relationship. That ain't love. And like the saying goes "once a cheater......"
By the way, just out of curiosity, when was the last time a super hot chick slipped you her thong underwear with her number written on it? Today, yesterday, the day before, last week, last month or like for most guys NEVER?!!!
The Alpha Male hunts his prey, and a hot chick is top notch game. The regular average guy is more likely to only look and enjoy the view as she struts her stuff right pass him. Most likely staying in the "fantasy" zone, not ever trying to make it reality.
Every woman knows men fantasize about other women, and they usually know which men will only fantasize, but any woman at anytime can change a mans behavior.