Alexander Villaluna attacked Keith Collins, who was on a first date with Jovi Pilapil, at a restaurant in Hornsby shopping centre in March 2016.
As ABC News reports, Villaluna stabbed Mr Collins in the stomach and neck 10 times with a hunting knife, and also attacked his former girlfriend Ms Pilapil in the chest and arm. He then fled the scene.
The 46-year-old, who pleaded guilty to murder and wounding with intent to commit grievous bodily harm, was sentenced on Thursday.
During sentencing, Justice Beech-Jones described Villaluna as “an almost textbook example of a perpetrator of extreme domestic violence,” Nine News reports.
“One of the most disturbing aspects of the CCTV, was the complete absence of any hesitation,” he told the court.
“That namely he would kill any man he thought was showing a romantic interest in his ex-partner.”
Justice Beech-Jones added: “Of all the cowardly and pitiless acts the offender committed on this day, his actions in returning to finish-off a dying man on the ground was perhaps the most heinous.”
Villaluna was sentenced to a maximum 34 years in prison for murder a maximum 12 years for wounding.
If you or someone you know is experiencing domestic violence, contact 1800 Respect (1800 737 732)
This article originally appeared on marie claire.