Spitzer: Oink, Oink
It's that simple.
All the pscyhological analysis is overwrought.
If he really had a destructive streak as many claimed he would have imploded a long time ago. Yes, he was arrogant and thought himself above the law.
But the plain reality is that he succumbed to his most base instincts.
Why was he so reckless? Didn't he fear getting caught or blackmailed?
Sex makes men reckless and do foolish things.
That's why it's sex.