Trefor Kingdon pleads guilty to murder of Mandy Melzer-Head after break-up argument

Mandy Melzer-Head was remembered by her daughters and cousin as the light of their lives. (Facebook)

A 65-year-old man who stabbed his partner 11 times following an argument over their separation has pleaded guilty to murder.

Mandy Melzer-Head and Trefor Kingdon were childhood sweethearts who reconnected at a school reunion before moving to the Mornington Peninsula.

They then moved to a 20-acre hobby farm in Bendoc, in the state's remote east.

On May 12, 2020, texts sent by Ms Melzer-Head indicated the relationship was over.

"Not sad, not drunk, not enraged," she wrote.

Trefor Kingdon, 65, pleaded guilty to the murder of his partner Mandy Melzer-Head.  (Facebook)

The Victorian Supreme Court heard both had been drinking — Ms Melzer-Head's blood alcohol content was 0.14 and Kingdon admitted to having six drinks.

Three hours later that night, Ms Melzer-Head called Kingdon nine times before he returned to the kitchen, grabbed a 32-centimetre kitchen knife and stabbed her.

A friend staying with the pair, John Osborne, woke up to Kingdon telling him "I think I've killed Mandy".

Mr Osborne called triple-0 and tried CPR for two hours but could not revive Ms Melzer-Head.

In questioning Kingdon's "disproportionate response" today, Justice Lex Lasry questioned the normalisation of men's violence against women.

Bendoc is more than six hours east of Melbourne, making it one of Victoria's most isolated towns. (ABC Gippsland: Emma Field)

'Burdened with darkness'

Both of Ms Melzer-Head's daughters had returned from careers overseas to grieve for their mother and organise her estate.

Her youngest daughter, Alexandra Head, told the court she had come back from Cambodia where she had been working in a gender equality development program.

"The day after Mother's Day, you took my mum," she said.

"You have burdened me with darkness."

Ms Head said she was considering changing her career due to severe post-traumatic stress caused by her mother's death.

Eldest daughter Georgia Head told the court her mum was "desperate to be a grandmother". 

"I miss you with all that I have," she said.

'Genuine empathy'

Kingdon's defence argued several factors should be considered to reduce his sentence.

A psychologist's report found Kingdon had a "genuine empathy" for the trauma he had caused. 

The defence also implored Justice Lasry to consider his age in the sentencing and the early stage of his guilty plea. 

Kingdon is expected to be sentenced in coming weeks.