Kristen Stewart cheated on Robert Pattinson with married director Rupert Sanders

Several U.S. and UK media claim that the actress has indeed cheated on Robert Pattinson.

The relationship between Kristen Stewart and Robert Pattinson has been shaken by the revelation that the actress had a brief affair with a married director, as stated by People.

“Kristen is absolutely devastated,” a source told the magazine. “It was a mistake and a complete lapse in judgment.”

Stewart had the fling with Snow White and the Huntsman director Rupert Sanders recently, the source claims.

“She wasn’t having an affair with Rupert. It was just a fleeting moment that shouldn’t have happened,” the insider says. “She never meant to hurt anyone. She’s a good person who just made a bad choice.”

Kristen Stewart and Rupert Sanders were caught in the act by photographers, according to Us Weekly.

“It seemed like they couldn’t get enough,” a photographer tells the magazine.

Rupert Sanders is married to British Vogue model Liberty Ross, 33, with whom he has two children, aged 7 and 5.

However, Kristen, 22, and Robert, 26, seemed happy a few days ago at Comic-Con. They were seen laughing and joking together.

The couple has been in a relationship for four years. They got together shortly after they started filming the Twilight saga.