Passion is the evil in adultery. If a man has no opportunity of living with another man's wife, but if it is obvious for some reason that he would like to do so, and would do so if he could, he is no less guilty than if he was caught in the act.
All works of art are commissioned in the sense that no artist can create one by a simple act of will but must wait until what he believes to be a good idea for a work comes to him.