This month my name is Mary. My name is different every month—Brandy, Honey, Amy…sometimes Joe doesn't even bother to ask—but he never fails to arouse me with his body, his mouth, his touch, no matter what I'm called or where he picks me up. The sex is always amazing, always leaves me itching for more in those long weeks until I see him again.

My real name is Sadie, and once a month over lunch Joe tells me about his latest conquest. But what Joe doesn't know is that, in my mind, I'm the star of every X-rated one-night stand he has revealed to me, or that I'm practically obsessed with our imaginary sex life. I know it's wrong. I know my husband wouldn't understand. But I can't stop. Not yet.