A NSW man sued his own wife for negligence after she failed to brake as he leapt from their Mercedes-Benz during a heated argument.

Brian Lim and his wife Eunkyung Cho had been out for dinner with their two young children in the Sydney suburb of Belmore on December 15, 2012 when they began to argue.

The couple, who had been married for five years at the time, continued to fight as Ms Cho drove the family home, and Ms Cho “made an insulting comment” about Mr Lim’s parents.

He then told his wife he wanted a divorce, and as the car passed the Australian Catholic University on Barker Rd, Strathfield, Mr Lim opened the passenger door as the car was in motion.

Ms Cho continued driving, but leaned across to grab her husband, telling him to “stop being silly”.

But Mr Lim jumped from the car, and suffered “catastrophic injuries” in the fall, according to legal documents seen by news.com.au.

Mr Lim then sued his wife for negligence, arguing she had failed to apply the brakes after seeing he planned to jump from the vehicle.

After hearing evidence from several traffic accident experts, Judge David Wilson dismissed Mr Lim’s case, finding his wife had been driving at around 50km/h when he jumped and that if she had braked, she could possibly have injured her children or other road users in the process.

He also found she had “acted reasonably when confronted with a sudden emergency” and therefore had not breached her duty of care to her husband.

Judge Wilson also ruled that Mr Lim was guilty of contributory negligence and that any damages owed to him would be reduced by 100 per cent.

Mr Lim tried to appeal that original decision in the NSW Court of Appeal, but on Monday his claim was dismissed.

Acting Justice Ronald Sackville said the case was “both unusual and tragic”, but agreed with the first District Court judge, finding that while Ms Cho did have a duty of care to her husband, she was not responsible for his decision to jump, which had previously been described as “stupid” but also “entirely out of character”.

Acting Justice Ronald Sackville said Ms Cho had found herself in an “extraordinary and unexpected situation that unfolded in a matter of a few seconds”.

“Not surprisingly, at first she did not grasp that the appellant would act as recklessly as he did,” he said.

“Her immediate reaction to the situation with which she was confronted was to attempt to prevent the appellant leaving the vehicle by reaching for him and telling him not to be silly. “As the primary Judge found, whether or not the respondent had an alternative course open, her actions in the fact of an unexpected emergency cannot be characterised as unreasonable.”