I think it is likely that Kratos will kill himself, especially if he can't rid himself of the nightmares/visions of his past. After all, that's what happened in GOW1, before the gods intervened.
I certainly don't think there will be a "happily ever after ending."
We know this is the last chapter for Kratos. However Santa Monica say they would like to continue the franchise with maybe Norse or Egyptian etc mythology.
When did they say that?
In the game Informer magazine. They said that they may continue the franchise, but as far as Stigs concern, God of War III is the last game.
Since the game is based on betrayal I think the titans will turn on him once he finishes killing off the gods.
I've been thinking the same thing.
Me too. The Titans will tell him that with the crimes he has commited that he cannot go unpunished, and that he has nothing left to live for now that he has had his revenge. He will fight the Titans because of the betrayal and yet accept his defeat to end his own suffering.
Classic greek tragedy, folks!