Disclaimer fo those of you who get your panties in a wad anytime a book reader posts: This is speculation here, not anything I've picked up from reading farther in the books.
I think Petyr is going to end up having a pretty gruesome, awesome death. He's played with fire and though he's really good at playing the game, I think he believes he's unbeatable. With all the other high quality players running around sooner or later he's going to lose.