'Happy Valentine's Day! Now cut your losses'

It's been said before, but Megan McArdle (BloombergView) puts it well; here's an excerpt:

Tomorrow night, at restaurants across the land, men will whip rings out of their pockets and try to find some vaguely original way of asking the woman across the table if she would like to spend the rest of their lives together raising children, choosing furniture and arguing about just how clean the bathroom vanity needs to be kept. At many other tables, women will be hoping for a proposal that doesn't come. If you are in that second group, I have some hard news for you: It's probably time to leave.