Adelaide man Peter Rex Dansie has been sentenced to life in prison, with a non-parole period of 25 years, for murdering his wife in Adelaide's parklands in 2017.
Dansie, 71, drowned his 67-year-old wife Helen Dansie by pushing her wheelchair into a pond at Veale Gardens in Adelaide.
Justice David Lovell established a "dual motive" for the murder – a deterioration in Dansie's feelings for his wife and an interest in pursuing a sexual relationship with another woman in China.
The court previously heard Dansie was scheduled to fly to China, but the day before he was due to leave police searched his home and found a suitcase packed with condoms, Viagra, sex toys and lingerie.
Helen Dansie died when her husband pushed her wheelchair into a pond. Photo: SA Police
During sentencing, Justice Lovell said Mrs Dansie's murder was the "ultimate act of domestic violence" and described it as an "evil and despicable act".
"This was a chilling, planned murder of a person whose only mistake was to trust you," he said.
"It was a planned murder – I'm not able to say precisely when you formed the intention to murder Helen.
"Clearly it was taking shape in the months leading up [to] that Easter Sunday."
He said Dansie made "no attempt" to save his wife once she was face-down in the pond at Veale Gardens.
Dansie – who is appealing against his murder conviction – was found guilty in December.
During the trial, prosecutors alleged Dansie murdered his wife because he regarded her as a cost burden.
Mrs Dansie, a former microbiologist, suffered a stroke in the 1990s that left her with long-term disabilities.
She was on an indexed pension for life, a large portion of which Mr Dansie was entitled to as her full-time carer, the court previously heard.
Mrs Dansie's son Grant said sentencing should send a message. Photo: AAP
Family calls for review to protect 'the most vulnerable'
Mrs Dansie's friend, Eugenia Giorgio, read a statement on behalf of her son Grant Dansie, saying he hoped sentencing sent a message.
"We hope this sends a message about protecting the rights of the most vulnerable," she said.
"At the same time we hope to see a thorough review of how the government deals with the rights of the most vulnerable to fill the gaping holes in the system that's meant to protect them."
Grant Dansie previously said he was pleased justice had been served.
"The greed, callousness and lack of humanity was despicable and I'm very satisfied with the verdict," he said.
"My beautiful mother belonged to three vulnerable groups – she had a disability, she was elderly, and she was a victim of domestic violence.
"Yet she managed to fall through all of the supposed safety nets. This isn't good enough."