Cherrington (51), a caregiver, was sentenced to six years and one month's prison for attempted murder on August 27 last year, which she had previously admitted.
She had been remanded in custody for sentence. Justice Whata imposed no minimum period of imprisonment.
She was given a first warning under the ''three strikes'' legislation.
Justice Whata said upon seeing the man and his wife walking in South Dunedin, Cherrington reached a ''tipping point'' into extreme violence, for which she had not previously shown much propensity.
Cherrington had an ''emotional fragility'' and an alcohol-abuse problem, in the context of a long and turbulent relationship with the victim. She was not a ''battered woman'' and was in good physical and mental health, he said.
That she blamed the authorities for not stepping in to the situation before the violent offending displayed a lack of remorse, although she did have insight into her offending, he said.
She had felt as though she was treated as a ''part-time partner'' by the man for whom she had relocated from Auckland to Dunedin.
In the psychiatric report that concluded she was not mentally ill, she exhibited a ''somewhat idealistic'' view of the move to the South, Justice Whata said.
Noting Cherrington had completed a drug and alcohol addiction programme since her offending, Justice Whata gave credit for an early guilty plea, which helped reduce the sentence from its starting point of eight years and six months.
She was described as an excellent rest-home employee, who went the extra mile, he said.
It was fortunate the weapon was a peeling knife, or the injuries would have been more serious, he said. Justice Whata suppressed the victim's name and any information that might identify him.
The summary of facts said Cherrington and the victim were in a relationship for about 12 years. Cherrington moved to Dunedin about two years ago.
The victim has been separated from his wife for about three years.
On August 22, police attended a domestic verbal argument between Cherrington and the victim at their Green Island home, and the victim agreed to move back to his mother's house to defuse the situation.
On August 27, the victim and his wife were walking in South Dunedin, when Cherrington drove past.
She drove to her daughter's house, called the victim, and told him she was going to come and get her key from him. She also told him she was going to kill him.
Cherrington and her daughter then left the house to go shopping, and Cherrington asked to stop off at her home to pick up hand cream and alcohol.
While there, she took a peeling knife from the kitchen, placing it in her pocket to hide it, before dropping it in the footwell of the car.
She told her daughter to head to the victim's mother's house to pick up her key.
The victim was waiting outside the house. He approached the car to hand over the key.
Cherrington opened her passenger door, picked up the knife, approached him, and started swinging her arms in an attempt to punch him.
The victim came forward and held on to her in a bear hug.
Cherrington stabbed him seven times in the back, and once in the neck.
The victim threw Cherrington to the ground, restraining her by sitting on her chest, and pinning her arms to the ground with his knees.
A bystander approached and helped remove the knife from Cherrington's hand.
The victim sustained a punctured right lung and other stab wounds.
Cherrington told police she wanted to kill the victim, and that she would have continued stabbing him had it not been for a lady who was screaming.
Cherrington said it was lucky the victim had been wearing a sheepskin jacket, and that if had it not been for her daughter's presence, she would have used a longer knife.
