When the marriage broke down, she moved out with the children, taking some of their things, leaving him on his own at the home.
The court had previously been told that, on October 8 last year, Scoullar drove to a Green Island service station and filled several containers with petrol. Shortly afterwards, he bought matches and returned home. He drank 18 bottles of beer, wrote suicide notes, and then doused several rooms with petrol before setting the house alight.
The amount of fuel in the house had an "explosive effect", shattering windows, some of which landed on the roof of a neighbouring property eight metres away.
The fire quickly engulfed the house - owned by the Scoullar Family Trust, according to court documents.
Scoullar sustained singed hair and burned clothing as he fled the property, but was able to drive away from the blaze, the court was told.
When he returned to the scene about 10pm, police officers concerned about his state of intoxication ordered him to undergo a breath test.
Scoullar refused and was taken back to the police station where a blood test gave a reading of 140mg - nearly three times the legal limit. The house was insured but that policy was void due to his actions.
Defence counsel Sarah Saunderson-Warner said today her client was suffering from "significant levels of stress" at the time of the incident.
He had been struggling financially with his business for some time, and the marriage break-up compounded his misery.
"The defendant felt a high degree of humiliation in regards to failures he felt were occurring in his life. He said it was the greatest moment of failure he's had in his life," Ms Saunderson-Warner said.
"He didn't do it because he wanted to punish the victims . . . he was angry with himself and failing he saw in his own life."
But Judge Phillips said he did not believe Scoullar intended to kill himself.
"It was done expressly to cause her harm, there can be no other reason for it," he said.
"You weren't considering suicide at all. You got in your car and ran off."
Scoullar's ex-partner agreed in her victim-impact statement - his actions were intended to punish her, she believed.
Judge Phillips was not convinced that Scoullar felt remorse for what he did, despite him apologising to her at a restorative-justice conference.
A probation officer said Scoullar exhibited no meaningful expressions of sorrow for the impact on his wife and children in a pre-sentence interview.
Judge Phillips also banned Scoullar from driving for 10 months, but any reparation order made by the court would be futile, he said.
Ms Saunderson-Warner said her client had used his time in custody productively and was committed to continue doing so.
Scoullar had taken up yoga, she said, and was using it to "become calmer and reduce his stress".
