A Sydney restaurateur accused of murdering her husband did not mean to inflict the knife wound but was reacting to a "very nasty situation", a jury has been told.
"What happened was a terrible, tragic accident and it occurred when she was trying to make sure her husband could not regain control of the knife," defence lawyer Phillip Boulten SC said in the NSW Supreme Court on Wednesday.
He was giving his final address at the trial of Qian Liu, 35, who has pleaded not guilty to murdering Han Lim Chin, 39, who was stabbed late on January 3, 2016, at their Riverwood granny flat.
She told the jury of arguments about his unfounded suspicions that she was having an affair with her personal fitness trainer.
On the night of January 3, she said she had grabbed a sheathed kitchen knife she had seen him put in the bumbag he was wearing, but had no idea the cover had come off it when she turned towards him holding it.
In the crown final address, prosecutor Brad Hughes SC referred to the force required to inflict the fatal injury, describing it as a "penetrating wound" rather than a minor flesh wound.
While Mr Chin was a troubled man, he was not violent.
The evidence revealed he was in debt, he was fearful of being caught for stealing from his employer, he had self-harm marks on his arms, and was jealous and suspicious of his wife.
"What the evidence does not reveal is that he was ever violent to his wife or that he was violent on the night of January 3," he said.
"She had the knife, she caused the fatal injury.
"Is her version, in parts, contradictory? Is it, in parts, implausible?"
Mr Boulten told the jury Liu was not guilty of murder or manslaughter, saying she had not meant to inflict the wound but had found herself in a very nasty situation.
Her husband was acting very irrationally, unreasonably believing she was having an affair, and reacted very badly when she rebuffed him that night.
Mr Chin was distraught, angry and aggressive. He had introduced the knife into the dynamic as a means to scare and intimidate his wife, the lawyer said.
"What she did when the wound was inflicted she did not do deliberately," he said.
The trial is continuing.