About David Petraeus: "The man falls in love with... himself!"

That's what I wrote, when I first saw that the man's love interest was the woman who wrote a fawning biography about him. It reminded me of John Edwards, falling for the woman who was trotting around after him videographing what her trotting around videographing made seem like the amazing wonder of his very being.

A reader emails:

"The man falls in love with... himself!"

And that is at the center of what an affair is about.

Here's Shirley Glass, who before her death a few years ago was considered one of the top experts on infidelity:

There is an attraction in the affair, and I try to understand what it is. Part of it is the romantic projection: I like the way I look when I see myself in the other person’s eyes. There is positive mirroring. An affair holds up a vanity mirror, the kind with all the little bulbs around it; it gives a nice rosy glow to the way you see yourself. By contrast, the marriage offers a make-up mirror; it magnifies all your wrinkles and pores, every little flaw. When someone loves you despite the fact that they can see all your flaws, that is a reality-based love.

In the stories of what happened during the affair, people seem to take on a different persona, and one of the things they liked best about being in that relationship was the person they had become. The man who wasn’t sensitive or expressive is now in a relationship where he is expressing his feelings and is supportive.