UH OH! Kristen Stewart Cheated On Robert Pattinson With Married Movie Director! (PHOTOS)

Could this be the end of our favorite Twilight couple?!

Kristen Stewart's relationship with Robert Pattinson may be on the rocks after she found love with another man!

The 22-year-old Twilight actress reportedly cheated on Robert with Rupert Sanders, the director of Snow White and the Huntsman. Kristen, who couldn't get enough of the 41-year-old, was reportedly photographed in his arms!

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According to People Magazine, a source said of the fling: 

"Kristen is absolutely devastated. It was a mistake and a complete lapse in judgement. She wasn't having an affair with Rupert."

Rupert, who is married to model Liberty Ross, has two children. 

The source continued:

"It was just a fleeting moment that shouldn't have happened. She never meant to hurt anyone. She's a good person who just made a bad choice."

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Recently, Rupert's 33-year-old wife spoke on the subject, tweeting:

"Sometimes good things fall apart so better things can fall together"

However, she later deleted her Twitter.

Is Kristen now considered a certified homewrecker or is this all a misunderstanding? 

SOURCE: People