In an exclusive interview with Radio-Canada’s Enquête, he wondered what more could have been done to protect Laurélie, 5, Loïc, 4, and Anaïs, 2.
Their mother, Sonia Blanchette, is accused of three counts of first-degree murder.
Today, a date for her preliminary hearing was set for June 21.
Desautels originally shared custody of their three children with Blanchette.
The father said she regularly forbade him from seeing the children after their break-up.
Desautels told Radio-Canada Blanchette even left with the children for six weeks without leaving contact information.
“I couldn’t have claimed contempt of court,” he said.
“I didn’t know where she was. And what would it do? Absolutely nothing. The police can’t do anything, and Youth Protection told me it couldn’t do anything.
“All I could do was wait and worry,” he continued.
Quebec’s youth protection services didn’t look into the case since Desautels couldn’t prove his children were in danger.
Blanchette was arrested for kidnapping at the end of 2011 for another incident.
A Superior Court judge ruled she couldn’t keep custody of her children, and could visit them only under professional supervision.
A few months later, the court said Blanchette could see them at her home, as long as her own mother supervised the visits.
But the grandmother told Radio-Canada she never received instructions on how to supervise the visits.
University of Montreal family law professor Alain Roy said that’s a less than ideal way of doing things.
“It seems to me to be extremely problematic. The process has to be tighter so that designated family members receive at least a training,” he said.
It was the grandmother who found the children dead in Blanchette’s apartment on Dec. 2, 2012 after having left at her daughter’s request.