Men cheat on their wives because...drum roll please....
Because sex is tempting, and some men don't deal with temptation as well as others. Or, some people deal with temptation better than others, depending on your perspective. The truth is that lust is universal. Some will resist, others will succumb. Some will resist and still succumb, and others yet will relish the chance to give in but never find the opportunity.
I am soooooooo tempted to start a thread "Why do wives cheat on their husbands" because I just know that the intellectual hoops will become tighter, and set ablaze in an attempt to come up with the most convoluted explanation possible. Plus it would be somewhat humorous to see the "Women are scum" crowd offer up their opinions.
Just FYI, I found the whole notion that if the little woman is the man's fantasy, he'll never lust after another more than just a little laughable. Hopefully a marriage will have something stronger than hot sex behind it. It's much easier to lust after taught and tawny 22 year old than it is your 42 year old wife of 11 years (that would be my wife). You've never seen taught, young and tawny (hereafter TYT) with a runny nose. You've never seen vomit in TYT's hair. You never saw TYT's redneck grin (missing teeth)in the weeks between extraction and bridgework, etc etc etc.. TYT has never seen you in any of those situations as well, and it shows in the way she looks at you. If you knew that TYT had seen you cry like a baby the night the dog sniffed your butt, and you blew whiskey through your nose, you'd interpret her looks a little differently too.
The point being: Daily living is not sexy, and daily living is what marriage is all about.
You don't need a special thread for that crowd. On FR, Every Day is Women are Scum Day!!!