I believe the title sums it up mostly. As the women here love to say, men will stick their dick in anything. Men have a low attraction floor, so they'll have sex with most women. A man's standard for sex vs lifetime commitment are very different. As such, women with "wifey material" qualities are seen as more valuable, respectable, and desirable than those without. The same way women employ a dual mating strategy, I believe men do the same.