Kristen Stewart, 22, had an affair with director Rupert Sanders, even though she was in a three-year relationship with the actor.
"Kristen can't believe the public isn't painting Rupert Sanders as the bad guy. She's grousing that he's 19 years her senior and was in a position of power over her ... being a director of a movie she had just shot and presumably someone she was going to work with again," tmz.com quoted a source as saying.
The actress is also upset about being called a cheater. Although she accepts her actions were wrong, but believes that Sanders is at a more culpable situation as he is married and has two children.
Stewart met the director on the sets of movie, "Snow White And Huntsman".