I just have to link to this post from Dan Ariely's blog:
The best part is an ingenious experiment with photographs that shows that people are happier with the photograph they produce (in a darkroom) if they can only choose one, early on. Those who are told to choose two and "think about it" and then decide which one? They end up being less happy with the photograph they chose.
It's a bit of a jump from that to marriage, but I do think it shows that the faithfulness and "locked-in choice" required by the institution of marriage will actually make you happier than "playing the field," even if you're not "optimizing your choices." There's such a thing as too much choice: Dan Ariely's social economics research has shown this repeatedly.
Boy, even if economics has romantic implications, the language of the field sure does scour the romance out of everything ... So, however that all sounded, it was meant well, and here's to faithfulness and our 10th Valentine's Day together, Laurie!