Rusty Yates told The Associated Press that Andrea Yates never told him, "I finally did it" in her telephone call to him after the drownings, as a Houston police officer testified during her second trial.
"It's been printed in papers as fact, and it's absolutely not true," he said. "Much of the state's case was built on lies."
A jury on Wednesday found Andrea Yates in the June 2001 bathtub drownings of her children. She was retried after her 2002 murder conviction was because of erroneous testimony about a nonexistent "Law & Order" television episode.
On Thursday, the 42-year-old was committed to the maximum-security North Texas State Hospital in Vernon.
Hospital officials will review her mental state and decide whether she is a danger to society. State District Judge Belinda Hill will review that report and hold a hearing within 30 days to determine if Yates should remain there or be moved to another state hospital.
During the interview, Rusty Yates said that on the day his children died, Andrea had called him and asked him to come home. When he and his mother arrived and learned from police what had happened, he reminded his mother that Andrea had filled the bathtub for no apparent reason about a month or so earlier.
"I said, `I guess she'd been thinking about this for some time and finally did it," Yates said. He said an officer must have overhead the conversation and took it out of context.
Prosecutors also seemed to change their theory about his now ex-wife's motive, Yates said.
"In the first trial, they said Andrea did this to try to get out, whatever that means, which sounded like she wasn't happy at home ... and this time they said she wanted to run off with me into the sunset," he said. "Well, which is it?
"The fact is, they spent five years and still don't have a reason why she did it because they are unwilling to look at the fact she was psychotic. That's the only reasonable explanation for her behavior."