Spin off from the other thread...Do you think cheating is more likely to arise when there are serious problems with a relationship to start with - and hence people look elsewhere for fulfillment or an escape - or do you think it happens frequently when relationships are fundamentally sound but people put themselves in tempting situations that at some point they can't resist (close friendships with members of whatever sex they are romantically attracted to, excess alcohol consumption, etc)? Or something else?