A Gold Coast man who was having an affair with a masseuse told his wife he'd had enough of her before he ploughed their car into a river, killing her.
Edward Kenneth Lord, 56, is awaiting sentencing in the NSW Supreme Court after pleading guilty to the manslaughter of his wife Michele in October 2015.
He failed to apologise in a Sydney courtroom packed with her family and friends on Thursday, despite having the opportunity to express remorse for the first time.
Lord's barrister, Jason Watts, claimed the concreter acted spontaneously when he drove their Nissan coupe into the Tweed River and the couple had previously enjoyed an "excellent" day together.
However, court documents reveal he had proposed to a woman he met in a Thai massage parlour and had a loud argument with his wife shortly before he deliberately drove off the Tweed Valley Way in northern NSW.
A week before the incident, Michele Lord went to police claiming her husband had attempted to drug her by putting a sleeping tablet in her wine.
She told Queensland Police he did it so he could have sex with Malaysian national Siew Ping "Margaret" Fong.
Lord had been having an affair with Ms Fong for months before he moved her into the couple's home as a maid in 2015.
Lord had met Ms Fong - who came to Australia on a tourist visa - while she was working at a Broadbeach massage parlour.
He convinced his wife to let her stay in the downstairs bedroom, telling her Ms Fong could help with housework given Ms Lord was working long hours and had been ill with breast cancer.
Police did not undertake any further inquiries into Ms Lord's claim that her husband had attempted to drug her - despite her providing evidence including a glass with white residue on it.
A week later the couple drove from their home at Bonogin in the Gold Coast hinterland to Byron Bay for a day of shopping on October 18.
It was on that trip that Lord intentionally drove into the river.
Despite Lord telling detectives the married couple were in a harmonious relationship, he had proposed to Ms Fong in August and given her an engagement ring.
However, Mr Watts described his client's actions as "spontaneous" and told the court "they spent the day together driving around and eating and shopping and from all reports had an excellent day".
"It's not like other domestic violence cases where there is a history of assault and a wife is in fear," the defence lawyer said.
During the drive back from northern NSW, Lord and his wife stopped at a car park off Tweed Valley Way, during which they were overheard by a fisherman having a heated argument.
He was heard speaking in an aggressive manner and telling his wife: "I've had a f***ing enough of your s***." Ms Lord was heard saying: "Just take me home."
A short time later, about 10pm, Lord intentionally veered the car off a road, down a rock sea wall into the Tweed River.
Ms Lord died in hospital two days later after her life support was turned off because of non-survivable brain injuries.
Lord told police at the time: "We were driving along having a laugh. The front left wheel slipped on the verge."
Justice Ian Harrison said Lord had failed to accept responsibility or display any remorse.
He will be sentenced on February 21.