Maybe it was because he suggested that she was going to hell?

From AP:

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.

The Gibsons released a joint statement Monday, seeking privacy.

"Throughout our marriage and separation we have always strived to maintain the privacy and integrity of our family and will continue to do so," the statement read.

Never good to see a marriage break up. But I found this unseemly interview awhile back:

Gibson was interviewed by the Herald Sun in Australia, and the reporter asked the star if Protestants are denied eternal salvation. “There is no salvation for those outside the Church,” Gibson replied. “I believe it.”

He elaborated: “Put it this way. My wife is a saint. She’s a much better person than I am. Honestly. She’s, like, Episcopalian, Church of England. She prays, she believes in God, she knows Jesus, she believes in that stuff. And it’s just not fair if she doesn’t make it, she’s better than I am. But that is a pronouncement from the chair. I go with it.”

Yikes. So she's a saint but she's going to hell?

Someone needs a theology lesson.

And apparently a good lawyer. Rumors of possible infidelity on Gibson's part have surfaced on a few gossip sites.