Charlie Sheen learned that defeat actually was an option in court today. The former “Two & a Half Men” star lost his custody battle with estranged wife Brooke Mueller for primary placement of their 2 yr old twins, Max and Bob.

Sheen and Mueller faced off before L.A. Superior Court Judge Hank Goldberg where Sheen’s lawyer, Mark Gross, lobbied that Mueller was unfit to care for the children. Her recent erratic behavior – hocking jewelry at a pawn shop, soliciting urine samples and refusing a drug test – and her decision to enter rehab over the weekend gave Sheen’s legal team the ammunition they needed to petition the court. After all, that drug test Mueller refused was one of the conditions of the custody agreement the couple reached in March – which gave her primary custody plus $55,000 a month in support.

TMZ reported that Mueller arrived first to the L.A. court where the custody hearing took place, followed shortly thereafter by Sheen. Members of the press were cleared from the courtroom not long after the proceedings began, however, when Goldberg announced that sensitive “questions of abuse” would be discussed.

A source inside the courtroom told RadarOnline the judge decided in Mueller’s favor. She will be allowed to keep primary custody of the two boys. The kids will stay with her mother, Moira Fiore, while she completes rehab at an undisclosed facility.

Mueller, who the source described as “unsteady on her feet” and “glassy-eyed” was smiling broadly as she exited the courthouse. She had no comment for the media.

Sheen departed for the airport directly from the courthouse. Destination? Chicago, to continue his “My Violent Torpedo of Truth/Defeat is Not an Option” tour. (If he had won custody, he intended to take the boys on tour with him, despite ex-wife Denise Richards‘ offer to take care of them in his absence.)

No word whether Sheen saw the twins while he was in town. They reportedly spent the day in the park with their nanny while their parents duked it out in court.