That's like asking if it would be a good idea to shoot yourself in the face if there is no damage done.
Perhaps i'm not trying hard enough to understand your meaning here, but are you saying this because in your opinion it would be impossible for such criteria to be met? As in its impossible for this to be done without somebody getting hurt?
Besides. Even if my wife never knew about it, I would, and I, having a conscience, would suffer, and ultimately lose some respect for myself, which would cause damage in my motivation and interactions for life.
Though i'm not married or committed to anyone, i think the same would happen to me. I'd always feel guilty of something.