Couples who cohabit before marriage (and especially before an engagement or an otherwise clear commitment) tend to be less satisfied with their marriages—and more likely to divorce—than couples who do not.
The problem is apparently that, unlike with marriage, couples slide into cohabitation without thinking much about it, but then are locked in anyway, and not necessarily happy about.
Happolati's Miscellany 
Wintery Knight has a decent essay on that piece here.
He seems to be missing the point. The issue isn’t that people cohabit for recreational sex, as he says, or that people today just want things to be easy. It’s certainly not that women are trying to avoid serious responsibility. The issue, as I understood it, was that women do think it’s a big deal, but men don’t. If anyone is trying to avoid responsibility here, it’s the men, so I don’t get why he spend the last two paragraphs talking about why women need guidance.
The women are of course foolish enough to give their charms away, and the men simply figure, as per the old adage, ‘Why buy the cow, if I’m getting the milk for free?’ Morality aside, can’t say I blame them.
Foolish, yes, absolutely.