Sandra Bullock is reportedly preparing to cut Jesse James loose.

The Oscar-winning actress has prepared divorce papers to end her four-year marriage to the Jesse James is a Dead Man and former Monster Garage star after allegations recently surfaced that he had affairs with several other women, RadarOnline reported Monday.

James checked into Arizona's Sierra Tucson Treatment Center for a 45-day sex addiction treatment program, however he reportedly left over the weekend after Bullock refused to take his phone calls.  Bullock is currently surrounded by security because she is afraid that James -- who is reportedly staying with a friend -- will attempt to personally confront her, according to RadarOnline.

"Her attitude toward Jesse hasn't softened since she found out he was cheating on her," a source told RadarOnline. "She's been betrayed and cheated on and she's not getting over that."

James and Bullock -- who wed in July 2005 -- reportedly have a prenuptial agreement that specifically states that he would receive no money in a divorce if he cheats during the marriage, according to RadarOnline.

"If she divorces Jesse and proves he was cheating, which won't be hard, Sandra won't have to pay Jesse anything," a source told RadarOnline, adding that really isn't a concern for Bullock.

"Right now Sandra is not thinking about the money. She's protected financially. She's just trying to deal with this mess."

Last month, James was accused of carrying out an 11-month affair with tattoo model Michelle "Bombshell" McGee while Bullock was in Atlanta filming The Blind Side -- for which recently won the Oscar for Best Actress.

A second woman then claimed that she also had a two-year affair with James, while Los Angeles photographer Brigitte Daguerre subsequently stated they had sex four times after he hired her to do styling work for his West Coast Choppers in 2008.

A fourth woman has also come forward and claimed through a representative that she had an "intimate" three year relationship with James.

Last week, it was reported that James admitted to Bullock that he had affairs with seven different women before he left for treatment.

While Bullock is apparently preparing divorce papers, it is still unknown when she'll actually file them, according to RadarOnline.