Jealous NSW boyfriend guilty of murder

A jealous NSW man who stabbed his on-off girlfriend five times in the neck and left her to die in a "scene of carnage" has been found guilty of murder.

Michael James Quinn brutally killed Cherie Vize, 25, in the front yard of his Wollongong family home before turning the knife on himself, in July 2013, leaving him quadriplegic.

Ms Vize, who had been going out with Quinn for about three years, had gone for a cigarette outside Quinn's family home in Wollongong when she was attacked by her partner.

Quinn 's mother Joanne tried to intervene.

"I noticed blood and Michael with a knife," she said while giving evidence at the judge-alone trial.

"I turned around and looked at Cherie and I saw that blood was pouring out from the side of her neck.

"When I saw the blood I instinctively reached out and put my hand on the wound to try and stop the flow of blood. As I did Cherie collapsed onto the ground on her back."

Quinn then stabbed himself twice in the chest and once in the neck with a small paring knife.

The OCD sufferer, who used to compulsively shower and scrub his legs, is now quadriplegic.

"I can't believe I missed my heart," he told his mother as he lay injured on the ground with a neighbour holding a towel to his neck.

Quinn denied murdering Ms Vize and told the court she had been injured while trying to stop him from hurting himself.

"The accused stated that he decided that it would be best for the deceased if he, that is the accused, took his own life as that would "allow Cherie to be free to do whatever she wanted," Justice Robert Beech-Jones said.

He told the court he had broken up with Ms Vize as he wanted her to be free from him and their toxic relationship.

But Justice Beech-Jones flatly rejected Quinn's account.

"Evidence to the contrary not only destroyed his reliability as a witness, but it demonstrated that he was a liar," he said.

Quinn had been dumped by Ms Vize and had seen a message on her phone about buying the morning after pill shortly before following her into the front yard and murdering her.

"Ms Vize was a peaceful person. Her passing has caused much sadness to her family and friends," Justice Beech-Jones said.

Her mother and supporters in court hugged as the verdict was handed down.

Sentence proceedings begin on October 14.

National domestic violence helpline: 1800 737 732 or 1800RESPECT. In an emergency call triple-zero.