Michael Was Weak and Whimpy
The guy was pathetic - between Peyton and Marlene, he was always being played and, in turn, playing the tease. And how gutless - couldn't protect his wife or kids, whined the whole movie, took Peyton's side every time, and in the end - somehow broke BOTH legs when he failed to apprehend her. And before that - had to be reminded by Claire how dangerous Peyton was, and could not convince the police to even show and take his call to them serious. A total failure as a husband and a father, and perhaps the weakest male character in film history.
Claire was selfish, completely unlikable, and a bad parent - but Michael was worse. I have no doubt she dumped him shortly after this ordeal. With Peyton gone, I'm sure that little kid went back to picking on Emma, and if Michael tried to interfere - the little kid would have whipped his weak ass, and knocked the snot out of him.