Having an orgy isn't unfaithful according to the movie bucket list. If you did have an orgy and you fucked someone other than your husband/wife, in what really are you not cheating on them? Its cheating as much as having an affair, it makes you as much of a hypocrite as anybody.
The guy/girl thought having an affair was cheating, but having an orgy wasn't cheating, what kind of hypocrisy is that?