But the older you get, the more cynical you become, and the more complicated and convoluted the exercise is. You begin to realize that nothing is perfect, that there are trade-offs and sacrifices. The worst is when someone in your past trumps the person in your present, and you think to yourself: if I'd known this, then maybe I wouldn't have let him go. I had been feeling that way for a long time with respect to my college boyfriend, Paul. My relationship with Paul was far from flawless, and yet I hadn't found anyone in a decade who could squelch the more than occasional longing for what we had shared.

But with Ben, something was different. I was happier than I had ever been. I told him this, and I remember him asking me why it was different, why I was happier. I thought for a long time, wanting my answer to be accurate and complete. I began to awkwardly detail what made my relationship with Paul fail and spent much time ticking off Paul's specific attributes and qualities. I then listed for Ben the ways in which he was better-and more important, better for me.

I said, "You are a better kisser. You are more even-tempered. You are more generous. You are smarter. You are more fair-minded."

Ben nodded and looked so serious that I remember saying, "And you recycle" just to be funny. (Although it was true that Paul never recycled, which I thought said a lot about him.) As I talked, I had the distinct sense that I wasn't really capturing the essence of the way I was feeling. It was frustrating because I wanted Ben to know how special he was to me.

So I sort of gave up and asked Ben the same question about his ex-girlfriend, Nicole. I had begun to piece together a pretty decent picture of her based on snippets of conversation. I knew she was half Vietnamese and looked like a porcelain doll. (I might have snooped through his drawers once and come up with a photo or two.) She was an interior designer and had met Ben on a big museum project in Brooklyn.