Charlie Sheen, Brooke Mueller File for Divorce

Charlie Sheen is about to be single again.

The actor, 45, and wife Brooke Mueller filed for divorce on Monday, TMZ confirms. Citing "irreconcilable differences," Sheen is seeking joint legal and physical custody of twins Bob and Max, 19 months; Mueller responded by filing for primary physical custody and joint legal custody.

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The couple -- who wed in May 2008 -- got into a violent fight last Christmas when Sheen reportedly threatened her with a knife. (Sheen pled guilty on lesser charges and spent time in rehab, not jail, for the offense.)

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Both husband and wife spent time earlier this year in rehab for alcohol and drug addictions. Just last week, Sheen was reportedly found intoxicated and naked in a Plaza Hotel suite in NYC; he allegedy flew into a rage and caused $7,000 worth of damages to the suite.

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After subsequent online reports suggested that Sheen was binging on cocaine and hookers back in L.A. and even close to death, his concerned manager stopped by the Two and a Half Men star's home over the weekend. "Charlie is fine and will be at work on Tuesday," the manager said in an email.

Even Mueller downplayed her estranged husband's most recent incident, telling Extra: "Charlie is a survivor. He knows how to handle himself. You know how things get blown out of proportion."