(Cover) - EN Showbiz - Robert Pattinson is reportedly grappling with whether "he should forgive" his girlfriend Kristen Stewart for cheating.

The 26-year-old actor is distraught after Kristen publicly revealed that she had a one-off liaison with director Rupert Sanders.

Robert is rumoured to have since moved out of the Los Angeles home that he shared with Kristen.

The Twilight star is said to be beside himself with grief over his partner's infidelity.

"[Robert's] really depressed," a source told Us Weekly magazine.

"He doesn't know what to do. He doesn't know if he should forgive her or not.

"Rob's whole experience of coming into fame was experienced with Kristen. This is going to be really tough. Nobody knows if they'll stay together at this point."

Kristen, who released a letter of apology to Rob Wednesday, is also overwrought with emotion.

"[She's] devastated," a second source revealed.

"She's very angry at herself. She's really not blaming anyone but herself."

Robert has been keeping a low profile in recent days and is said to be ashamed to show his face.

"Rob is beyond devastated," a third insider explained. "He's so heartbroken. He's shocked she could hurt him and humiliate him this way." (C) Cover Media