Patrick Clancy, the ex-husband of Lindsay Clancy, has given an interview with US current affairs program 60 Minutes.
Lindsay Clancy was charged with three counts of first-degree murder over the deaths of her three children Cora, Dawson and Callan on January 24, 2023.
Mr Clancy returned to the family's home to find his then-wife lying paralysed in their yard after trying to take her own life by jumping from a second-storey window.
Cora and Dawson were dead, while Callan was critically injured.
The eight-month-old died in hospital four days later.
Ms Clancy did not deny killing her children.
Mr Clancy's appearance on 60 Minutes comes after Judge William Sullivan declared a mistrial when a jury was unable to come to an unanimous decision on his ex-wife's guilt.
CBS reporter Ross Douthat asked Mr Clancy if his wife explained why she killed her children.
Mr Clancy said he did not know anything about postpartum mental illness before his experiences with his former wife.
In a clip of the interview posted to social media, Mr Clancy was asked if he felt like he failed.
Mr Clancy said "everything just came to a screeching halt" in the wake of the killings.
As Lindsay Clancy's trial unfolded, conspiracy theories circulated on social media, with some accusing Patrick Clancy of killing the children and framing his wife without evidence.
Ms Clancy rejected this theory, with her lawyer Kevin Reddington telling US broadcaster NBC campaign against Mr Clancy was a "nightmare that he doesn’t deserve".
Dr Danis said the pair met at a run club in New York in January, 2024.