If you date too many people, you'll never be happy. And while it's not a Puritanical retributive kind of punishment, you will, ultimately, end up miserable. It is simply this: When you've sampled all the cereals in the aisle, no single one will do. If you've had the firey and passionate relationship of a wild woman, and the quiet comfort of a woman who loves to stay in and read, you will never be able to reconcile the two. You develop a taste for mutually exclusive and irreconcilable goods. It is not that either is inherently better, but after a while you fall in love with them independently and implicitly seek an impossible combination in a mate, a white whale that is both a blonde and a brunette simultaneously. But Lucky Charms don't taste anything like Special K. And monogamy is an asshole.
Lock something down before you become unreachable. Choosy Moms who shop too long for the perfect peanut butter end up miserable.