TMZ quoted the filing as saying, "The marriage has become insupportable because of discord or conflict of personalities ... that destroys the legitimate ends of the marriage relationship and prevents any reasonable expectation of reconciliation."
Buffington-Quaid requested spousal support and the payment of attorney's fees, TMZ said.
The couple are the parents of twin 4-year-old sons. The boys nearly died shortly after they were born because the medical staff at Cedars-Sinai Medical Center in Los Angeles mistakenly gave them massive overdoses of the blood-thinning drug Heparin.
The Quaids subsequently sued the hospital and fought for better labeling on drugs in hospitals.