Hot bump 'n' grind on the sly

No, this isn't where I turn Nikki Gemmel. As of yesterday, beloved visits this site (and I'm still engaged, and still alive!). Just a hypothetical from a raging discussion held over a fine plate of Coopers-beer-battered Whiting and chips in a pub at the cusp of an Adelaide Hill.

"Which is the greater betrayal? "

A theory goes, and it is only a (biological determinist) theory...

Men, if they fool around, are driven to share their genes as widely as possible. In the tribal groups and pre-agrarian societies where these instincts were being honed there was no DNA testing or child support, so man's investment in the consequences of his actions was limited. Sex with a woman other than his partner had few risks. While he might choose the more attractive woman if facing a choice, he is not too discriminating. He can copulate with multiple women of varying degrees of attractiveness, and each act potentially furthers his genes. The instinctive residue of this is men today being, relative to women, indiscriminate and up for it.

Women, if they fool around, are driven to get the best genes possible. Until the incredibly liberating advent of the pill and control over their own bodies, a woman could get pregnant during any romp. Her fun could be heavy with long-term consequences. With no obstetricians birth itself is a mortal risk. So while women enjoy sex just as much, perhaps more, than men, they are highly discriminating. This carries into the present, where modern women who have no 'moral' problem with cutting loose and enjoying casual sex, and who are on the pill and have a bag full of condoms, still go about selecting partners in a much more cautious manner than males.

OK, it's generalisation, there are exceptions. And it's theory strongly opposed by the blank-slate school.

But a question flowing from this got a few of us arguing vehemently, and the split was precise along gender lines: if betrayed by your partner (obviously not good to begin with),

would it be worse that they did it with someone they don't find any more appealing than yourself, in a random act of opportunism, or if they did it with someone better looking or smarter or more successful than yourself because of the fact that the person is better looking or smarter or more successful than yourself?

Females felt that if you were betrayed because your partner couldn't resist a once-in-a-lifetime opportunity to be with a Johnny Depp, Gael Garcia or equivalent like Jolie or Longoria, that would be much easier to take than if it was with someone friendly you met in a bar one time. Men disagreed.

Thoughts? Experiences to share?