Numan Mohammed stabbed talented chef Kim Chau 110 times and inflicted wounds on her after she died in 2019.
He then hid her body and stole her car in an act of revenge.
The Supreme Court heard on Friday that Mohammed was fixated on his victim.
The refugee from Myanmar blamed Chau for his relationship breakdown with another woman and used his phone to search online “how many years for killing someone” prior to the attack.
In sentencing, Justice Anne Bampton said Mohammed’s offending was not on the lower end of the scale and there was a level of pre-planning involved.
She took into account his guilty plea and his show of remorse.
“Everything that happened in your life was taken out on Ms Chau during the confrontation with her at the Sturt Street premises,” Brampton said.
“You did not go there with the intent to kill but clearly the intent was present once the altercation started.”
Mohammed didn’t react when he was sentenced to life in prison, with a non-parole period of 23 years and nine months.
Chau’s nephew William said “nothing is going to bring Kim back”.
“Kim was a beautiful and kind person and was loved by many,” he said.
“We miss her every day.
“All her friends and family think about her every day.”