Jacques Delisle told Radio-Canada in an interview to be broadcast Thursday he lied because he was scared of what their family would think if they found out he helped her kill herself.
The former Quebec Court of Appeal justice, who is incarcerated at the Sainte-Anne-des-Plaines institution northwest of Montreal, did not testify at his trial but his lawyer argued Nicole Rainville, 71, committed suicide in 2009 without help.
The Crown alleged Delisle killed his wife in order to live with his mistress and avoid a costly divorce settlement.
He was convicted of murder and sentenced to life in prison in 2012. He tried unsuccessfully to have his conviction overturned at the Quebec Court of Appeal and the Supreme Court of Canada.
Delisle told "Enquete," Radio-Canada's investigative program, that in 2009 his disabled wife wanted to die and asked him to retrieve a pistol in the house.
He said he charged the weapon and gave it to Rainville.
The ex-judge added that before he left the house he tried to dissuade her from taking her life.
Rainville was found dead at her home with a bullet in her head.
Helping a person commit suicide is a criminal act and carries a maximum sentence of 14 years.
The CBC's French-language network also reported that Delisle's new lawyer, Toronto-based James Lockyer, will ask the federal justice minister to review his client's conviction. If the minister believes legal errors were made, he can order a new trial or refer the matter to the appeals court.
Lockyer, who helped found the Association in Defence of the Wrongly Convicted, refused an interview request.