I think that what Spitzer did was self destructive. He has body guards who know what he does and there are tabloid's that would pay a lot for embarrassing the Gov of a large state. He had to know that no matter how careful he was, it was only a matter of time, before the truth would come out.
So, yes Spitzer was probably self destructive or so self centered that he believed he would beat all odds.
Next, why would a man with a wife and young children at home want to cheat on his wife for over ten years? I think that he was searching for something that he didn't get with his wife.
Yeah, probably kinky sex.