Liberty Ross could not get past Rupert Sanders' affair with Kristen Stewart.
The British model and actress has filed divorce papers this week at the Los Angeles County Superior Court, asking for spousal support and joint custody of their children Sykla, 7, and Tennyson, 5.
A source close to the 34-year-old mother told USMagazine.com that she is still angry with her estranged director husband about his fling with Snow White and the Huntsman star Stewart, 22, and decided that she could never get over it.
"This was a long time coming," the source said. "Rupert did want to try to repair the relationship and didn't want a divorce" following his affair.
A second source said that Ross "was more than a little upset" about the betrayal, explaining: "They gave it a shot for the kids, [but] she was just so angry . . .she's the kind of person who wouldn't really ever get over it."
In response to the petition, Sanders has requested joint custody of the children.
Ross and Sanders' marriage has been under strain ever since his fling with Stewart was exposed last year.
Although Ross initially kicked the director out of their home after his infidelity was revealed, they began couples therapy in an attempt to save their marriage.
A source said at the time: "It was Rupert's suggestion that he go to therapy with Liberty.
"He will do anything to save his marriage because he loves his wife and knows he screwed up.
The couple had been married since 2003.
"Rupert is willing to do absolutely anything and everything he can to save his marriage, he knows this is the worst mistake of his life, and he cannot believe he was so stupid," the source said.
"The thought of losing his wife and children, who he loves more than anything in the world is killing him."