It's so easy to say that you shouldn't steal when you aren't poor. It's so easy to say that the Palestinians shouldn't kill Israelis when you aren't a Palestinian. It's easy to say that you shouldn't rape when you don't have some hot young girl teasing you and then denying you sex. Do you really believe any of those excuses? Do I really need to go on? I can play that game all day if you want.
If the standard is to be without sin before you can pass any sort of judgement on the actions of others, we better just repeal most laws because nobody is without sin and there is no law that somebody can't find some way to rationalize their way around. That's why that's not the standard, so you can put your straw man away.
And, frankly, if the life of a rock star makes adultery so inevitable, I have a simple solution -- don't be a rock star if you get married or don't get married if you want to be a rock star. Perhaps there is a reason why acting and entertaining were considered morally questionable occupations and women were, in various places and times, prohibited from those professions.