I’ll tell you why I cheat. I need to. Infidelity makes me remember things. The details that expand to fill my life (my upcoming performance reviews, the aches and pains of training, the recovery of my 401(k) ) and the ones that deaden it (my guilt, my smug self-satisfaction, my fake epiphanies about my progress in this life) —all of that drops away when I look down at the naked spine of an unfamiliar woman, twisting slightly in the late-afternoon sunlight streaming onto the sheets of a Hampton Inn in some nameless suburb. This is the most absolute choice I can make. I am there on my own. Against every code, rule, and set of mores I pretend to obey. Against better judgment, against every lesson of hindsight and every shard of wisdom that comes with age, I have no regrets in that moment, because I am naked, or without pants, and I have chosen to be there. I have voted by my presence, declared it, and I feel the blood moving in me again. So it’s the blood. That’s who I am. That’s why men cheat.

From the April 2010 issue of Esquire magazine. If you haven't read this piece already, I seriously recommend that you do.