Los Angeles (CNN) -- Maria Shriver cited "irreconcilable differences" in a petition filed Friday to dissolve her 25-year marriage to former California Gov. Arnold Schwarzenegger.
The move comes more than a month after Schwarzenegger acknowledged that he fathered a child outside of his marriage.
The couple announced their separation on May 9, calling it a mutual decision made "after a great deal of thought, reflection, discussion, and prayer."
It became clear a week later that the split was triggered by Schwarzenegger's revelation to his wife that he had fathered a child with his housekeeper.
"After leaving the governor's office I told my wife about this event, which occurred over a decade ago," Schwarzenegger said in a statement May 17. "I understand and deserve the feelings of anger and disappointment among my friends and family."
Shriver, in a written statement that same day, described it as "a painful and heartbreaking time."
"As a mother, my concern is for the children," she said. "I ask for compassion, respect and privacy as my children and I try to rebuild our lives and heal. I will have no further comment."
It was confirmed several days later that a son fathered by Schwarzenegger with his housekeeper was born less than a week after Shriver gave birth to Schwarzenegger's son, Christopher, who is now 13.
Shriver's signature on the divorce papers is dated June 18, but her lawyer filed them with the Los Angeles County Superior Court on Friday.
Shriver's petition proposed that she and Schwarzenegger share joint custody of their two minor sons, Patrick, 17, and Christopher. They also have two adult daughters, Katherine and Christina.
The date of their separation was listed as "to be determined."
The filing did not detail the assets to be divided between Shriver and Schwarzenegger
"There are community and quasi-community assets and obligations of the parties, the exact nature and extent of which are unknown to petitioner at this time," Shriver's petition said.
Schwarzenegger, a naturalized U.S. citizen from Austria who gained fame as the youngest winner of the Mr. Universe bodybuilding contest, was governor until January. He has been busy in recent months reviving his acting career and signing movie deals -- including plans for another installment of the "Terminator" series.
CNN's Paul Vercammen contributed to this report.