Actor Mel Gibson's wife of 28 years filed for divorce Monday, citing irreconcilable differences. Robyn Gibson filed the petition, which offers no details of the breakup, in Los Angeles Superior Court. The couple have seven children, but only one under 18. Robyn Gibson has requested joint custody of their son who turns 10 on Tuesday. Details of how the couple's assets will be divided were not spelled out in the court filings. Robyn Gibson is seeking jewelry and earnings and assets she accrued after the couple separated, and a share of the money and assets Gibson, 53, has earned during his nearly three decades as a Hollywood hitmaker. She wants the actor-director to pay spousal support and her attorney's fees. Mel Gibson filed a response to the divorce within hours of his wife's filing, stating that the couple separated in late August 2006. He does not want to pay Robyn Gibson spousal support and is seeking that attorneys' fees be paid out of the couple's joint property.