Brian Earl Johnston, 37, stabbed Kelly Wilkinson, 27, several times in the neck and chest before setting her alight in the backyard of her Gold Coast home in April 2021.
The estranged husband and former US marine was jailed in the Brisbane Supreme Court after previously pleading guilty to murdering the mother of three.
Wilkinson’s family, who were in court for the sentencing, said it was not enough.
“After 20 years he could be free at 55. My heart aches for Kelly,” her sister Danielle Carroll said.
“This is not justice for her, this is not justice for our family and this is not justice for future victims in our community.”
Wilkinson’s family remembered her as a “beautiful soul” with a “cheeky presence”.
Justice Peter Applegarth said he was limited by law in the sentence he could impose on Johnston and would likely agree with Wilkinson’s family if they said it was “not enough” for the “horrendous crime”.
When he handed down his sentencing, he said Johnston had committed a crime of “extreme domestic violence” with “planning and premeditation”.
“Kelly was not yours to control,” he told the convicted killer in court.
Johnston arrived at Wilkinson’s home armed with multiple knives and a 20-litre can of petrol before attacking her about 6.30am on her backyard patio.
Defence barrister Kim Bryson said Johnston was remorseful, and was exposed to domestic violence and excessive physical discipline as a child.
Bryson said Johnston had been discouraged from seeking mental health treatment during his military service for depression and post-traumatic stress.
Carroll told the court Johnston’s “pure evil” decision to destroy her sister’s body had robbed the family of being able to properly say goodbye.
“You have caused me and those around me a lifetime of immeasurable suffering,” she said.
Johnston will be eligible to apply for parole 20 years from the date of his arrest.
Another man was charged in July 2021 with murder and faces trial for allegedly providing assistance that was instrumental in the crime.
