A Sydney man convicted of killing his gay lover has wept as a lawyer told of his hardship in facing trial three times over the same death, an ordeal unprecedented in NSW.

Philip Leung, 51, was found guilty by a NSW Supreme Court jury in November last year of the manslaughter of his partner Mario Guzzetti at their Alexandria home in April 2007.

Leung had been acquitted in two trials in 2009 and 2011, after judges directed the juries to enter not-guilty verdicts based on a lack of evidence.

But successful appeals by the prosecution saw him retried under NSW's revised 2006 double jeopardy laws.

Leung pleaded not guilty in all three trials - firstly to a charge of murder and in the other two trials to manslaughter.

During a sentencing hearing on Friday, Leung's barrister Winston Terracini SC said Justice Derek Price faced a unique situation.

"There are no cases that will fall squarely within both the facts and the history of this matter in the history of the state," he told the court.

"He is the only person in the state who has gone through what he has gone through."

Leung, who continues to maintain his innocence, was found by witnesses cradling Mr Guzzetti's head at the foot of a staircase.

The crown alleged the couple argued while Leung was making carrot juice, resulting in him striking his lover with a juicer and applying pressure to his neck area.

On Friday, Leung sobbed loudly as the court heard how he had laboured to rebuild his life after two acquittals.

"There is a very significant effect upon him being able to cope both emotionally and physically with having what he thought was finality twice," Mr Terracini said.

He submitted Leung was unlikely to reoffend and the attack on his 72-year-old lover was not particularly savage.

Taking account of the three trials and the more than seven months Leung had already spent in custody, Mr Terracini said he should only be given a custodial sentence of one year coupled with extended supervision.

But crown prosecutor Mark Hobart SC said it was a "substantial attack" with evidence that Mr Guzzetti had been struck to the face more than once and sustained severe bruising on his neck.

In a victim impact statement read to the court Enzo Guzzetti said the three trials had brought "some relief" after the death of his brother, but questions remained.

"I would still like to hear from Philip the truth of what happened," Mr Guzzetti said.

Leung is set to be sentenced on March 28.

It is understood he plans to appeal his conviction.