Curtis McConnell is expected to testify about how he discovered the bodies of his two young sons floating in the bathtub of the family's home in Millet in February 2010.
Moments earlier, police had called McConnell to tell him his wife had jumped off an Edmonton overpass and was in the hospital with broken bones.
The couple were in the middle of a bitter divorce and fighting over custody of their children, aged 2 1/2 and 10 months.
Allyson McConnell has admitted to killing her sons but has pleaded not guilty to two counts of second-degree murder.
She was found mentally fit to stand trial in but remains a mental health patient at Alberta Hospital and is under around-the-clock suicide watch.