In this article, Goldman also says that a large study found that 90% of women were attracted to a man when she thought he was taken, while only 59% of them were attracted to him with the knowledge of him being single. I wonder, is it possible we are attracted to someone who appears as "safe"? Women are constantly approached and hit on, so maybe there is some level of attraction to someone who you think will not make you feel uncomfortable. I'm not sure. What I do know is this: in the casino bar I work at, a single male bartender will always wear a fake wedding ring. He puts it simply: he gets bigger, better tips from women when they think he is married.
Here's Dr. Goldman's full article for anyone interested: