DALLAS (AP) – A man whose mentally ill wife beat two of their sons to death with rocks has filed for divorce, citing personality conflicts and the interests of the couple’s surviving toddler.

In a divorce petition filed Thursday, Keith Laney seeks sole custody of 2-year-old Aaron, who was severely brain damaged in the attack at the family home in New Chapel Hill, 100 miles southeast of Dallas.

Laney’s wife, Deanna, was acquitted by reason of insanity last month in the deaths of Joshua, 8, and Luke, 6, and the beating of Aaron in May 2003.

Psychiatrists said Laney did not know her actions were wrong at the time because she suffered from psychotic delusions that God told her to kill her children.

Keith Laney had continued to express support for his wife after the killings, attending court hearings and testifying during her trial that he still loved her.

But in the divorce petition, he said they have not lived together since May 2003 and that their conflict in personalities “destroys the legitimate ends of the marriage relationship.”

Attorneys for Keith Laney, 45, and for Deanna Laney, 39, did not immediately return messages left Friday by The Associated Press.

The divorce petition does not mention finances as a reason for the split, but the documents were filed weeks after the state notified Keith Laney that he would have to help pay for his wife’s psychiatric care. By law, she could remain committed to a mental hospital for the rest of her life.

Texas pays for prisoners’ upkeep but does not cover all costs for confinement in a state mental hospital unless the family is poor. For others, it charges a sliding scale based on income and other factors.

Laney, an air compressor repairman, could be forced to pay thousands of dollars a month toward his wife’s care, which costs nearly $14,000 per month.

Don Rogers, a spokesman with Texas Department of Mental Health and Mental Retardation, said divorce does not generally free a spouse from having to pay for medical care received before the divorce. But divorce can free a spouse from obligations to pay for future care, he said. He stressed he was not commenting on the Laney case.