Robert Pattinson wants to have a little "chat" with Rupert Sanders over cheating girlfriend Kristen Stewart.

Heartbroken Robert Pattinson is desperate to know all the details of girlfriend Kristen Stewart's betrayal and he is ready to hear it from the man she cheated with, married "Snow White" director Rubert Sanders.

According to a source close to the "Twilight" star: “Rob wants to have a man-to-man chat with Rupert to find out exactly what happened between him and Kristen.”

Pattinson moved out of the L.A. home he shares with Stewart after the 22-year-old actress was photographed kissing the 41-year-old Sanders, according to the NY Daily News.

“Rob was really blindsided by this and he’s going through the typical stages of being cheated on,” said the source, “He was hurt and heartbroken, then angry and pissed off, and now he just wants answers. He feels like he needs to know exactly what happened, how far it went and how many times, so he can figure out if this is something he can move past. He’s not ready to talk with Kristen, it’s too painful, so he’s going to Rupert.”

Pattinson told Italian Vanity Fair last year: “There is one thing I’ve never understood. Why people cheat.”