Arona Peniamina, 41, was initially convicted of murder and ordered to serve the rest of his life behind bars after killing his wife Sandra at the family home at Kippa-Ring, north of Brisbane, on March 31, 2016

But the High Court tossed out the murder conviction on appeal, finding a crucial legal error by the judge during jury instruction at the 2018 trial, and granted Peniamina a new hearing.

Peniamina always admitted killing the mother of four, but he argued he should be convicted of manslaughter.

The jury at his retrial agreed, handing down a majority verdict on the reduced charge in Queensland's Supreme Court in September.

On the night of the brutal slaying, Peniamina had discovered his wife was having an affair and "lost control" when the pair argued over her infidelity.

Mrs Peniamina had started sleeping alone and had just returned from a trip to New Zealand, where pictures of her were posted on social media by another man.

A livid Peniamina talked to family members about her affair before returning home to confront his wife.

The pair argued in the bedroom, with Mrs Peniamina refusing to give him her mobile phone, and he lashed out, punching her in the face before escaping to the kitchen to arm herself with a knife.

He wrestled the knife from her, cutting his hand when he grabbed the blade.

He again punched her before stabbing her multiple times with the kitchen knife.

Experts found 29 sharp force injuries on her battered body - 15 to her head alone, with six penetrating her skull and one slashing her from nose to chin, exposing her nasal septum.

When she fled the home and tried to hide behind a car, Peniamina followed.

He threw his wife onto the driveway, kicking her before caving her head in with the bollard.

Police found the handle of the knife Peniamina used in the attack underneath the car, the blade nearby and the tip was later found embedded in her skull.

Justice Peter Davis handed down the reduced sentence on Monday, finding the killing was a "spontaneous reaction" with a partial defence of provocation.

"At the time you did the act that killed your wife, you had temporarily lost the power of self-control," Justice Davis said.

"Your attack on Mrs Peniamina was ferocious - you inflicted 29 sharp force injuries.

"Some of the blows caused very serious injuries ... some with such force that it penetrated Mrs Peniamina's skull.

"Your attack upon her was savage. You rained stabs down on her upper body, face and head.

"The pronged and vicious attack only ended when you killed her, by crushing part of her skull with a bollard.

"This violence was extreme and was inflicted in a domestic violence situation initiated by your reaction to your wife not doing what you wanted her to do."

Mrs Peniamina's family watched the decision by video link, fighting back the tears throughout the proceedings.

In a victim impact statement, her younger sister said their hearts would "never be mended".

"Our lives have changed in every aspect," the statement read to the court states.

"The boys have had to adjust to a whole new life - they are growing up without any parents.

"Sandra will miss seeing her boys grow. She has already missed her youngest's first day at primary school, she has missed the boys playing their first league games and missed them performing at school.

"Every day, we face an emotional battle knowing Sandy is not here with us.

"You took a life that was not yours to take. We miss her dearly."

Peniamina must serve at least 80 per cent of his 16-year sentence before being eligible for parole and will be deported on his release.

Australian Associated Press