I agree he's a horrible person, but all those things have nothing to do with Google and his position at Google or her position at Google. Those were relationship decisions they made on their own. They both made horrible personal decisions, but it doesn't involve google.
Except he was her boss at google, google forced her into a position she didn't want, and he encouraged her to quit under false pretenses.
This is a high level google executive engaging in grossly unprofessional behavior with one of his employees. It's abuse of both power and trust. As far as I'm concerned the judgement and behavior shown by him should make him completely untouchable.