Originally posted by: Jumpman

And the reason he does serve the Emperor after Padme is gone is because he has nothing else, but the Emperor. He's a shell of his former self so he can't beat the Emperor. He doesn't have Padme any longer. What else is he going to do?

Like I said, exile or suicide. At the end of Sith, he doesn't strike me as the guy who willingly dedicates his life to serving the Empire and its Emperor. The prequels don't give him that kind of dedication. Like you said, he's left with NOTHING. He has no reason to stay with Palpatine.