Los Angeles: Hollywood actor Robert Pattinson cannot get over ex-girlfriend Kristen Stewart's affair with director Rupert Sanders.
Pattinson caught Stewart cheating on him with the married director last year.
"Rob broke up with Kristen because he never got over the fact that she cheated," contactmusic.com quoted a source as saying.
"He is never going to forget. For a superstar, he can be very insecure and what went down last year just preyed on that. Rob gets in his own head and thinks the worst. He broods a lot," the source said.