you will NEVER find a perfect human being.

Your standards are simply to much to ask for a fellow human being.

You must allow them to be human, especially the ones that are trying to be extraordinary in so many other ways.  

And you are letting this ONE incident erase everything else he has done.

Not him, YOU.  Because you are the only one with the power to erase it, not he, because what he has done IS done.  You are the only one that can alter your memories of it.

And you have no idea of the context of the situation.  He could have sought out a call girl because his wife and he no longer have relations.  Yet you would demand of him that he let that side of his life die.....

That is not a reasonable request to make of another human being and you know it.