Victorian man jailed over arson killing

A truck driver torched his love rival's Melbourne flat to force his estranged wife to return to him, but killed the pair and their dog instead.

David Campbell will now remain behind bars for at least 10 years after being sentenced on Friday over the deaths of Genine Ballantine and her partner Steven White.

The 45-year-old says he believed nobody was inside the Deer Park flat at the time he reached through a broken window and set fire to a curtain in the early hours of September 20, 2013.

Ms Ballantine and Mr White, both 46, and their pet Jack Russell, were found dead in the master bedroom by emergency crews.

Justice Lex Lasry said Campbell had been to the unit a number of times in the weeks leading up to the fatal blaze, fighting with Mr White and breaking windows.

"You were hoping that by destroying the premises of Mr White, not only would he be severely disadvantaged, but Ms Ballantine would be forced to resume her relationship with you in order to have somewhere to live," he told Campbell.

The court heard Campbell's marriage to Ballantine had been marred by drug and alcohol abuse, and violence.

But the relationship between Ms Ballantine and Mr White was just as unstable, Justice Lasry said.

Campbell told police he lit the fire after overhearing, during a phone call, Mr White assaulting Ms Ballantine.

"You said you had done this as payback to Mr White because he had bashed Ms Ballantine," Justice Lasry said.

Two other people inside the Department of Human Services flat at the time of the blaze managed to escape.

Campbell, who pleaded guilty to two counts of arson causing death, was sentenced to 13 years' jail and will be eligible for parole after serving 10.

Speaking outside court, Mr White's mother Brenda McIntyre said the pain of losing her son would never go away.