The man who murdered the prominent Melbourne interior designer he'd been in a relationship with for 16 years was "damaged goods" when the pair met, a court has heard.
Michael Anthony O'Neill, 48, used a frying pan to bludgeon Stuart Rattle in December last year before strangling him with a nylon dog leash.
Now he can't sleep at night without the man he says was the most important person in his life, his defence barrister told a Victorian Supreme Court plea hearing on Tuesday.
"Michael has said to me from prison, often through tears, `I've destroyed everything'," O'Neill's barrister Ruth Shann read from a witness statement.
"'I can't sleep at night because I hate being by myself. I can't sleep without Stuart.'"
O'Neill admitted to killing Mr Rattle after police discovered inconsistencies with his story.
A blaze at the couple's Malvern Road apartment on December 9 was originally thought to be the cause of death.
O'Neill said he had set the couple's home on fire in a bid to hide what he had done, Crown prosecutor Gavin Silbert told an earlier hearing.
Ms Shann told the plea hearing O'Neill was "damaged goods" and that when he met Mr Rattle he had already established a ingrained pattern of shame, avoidance and repression.
The court had earlier heard he was a pathological liar and was referred to as "the talented Mr Ripley" by some people who knew him.
She said O'Neill's future is bleak and requested a shorter than usual non-parole period so O'Neill can attempt to find employment in his early 60s.
"He will continue to punish himself for his actions on the 4th of December and thereafter," Ms Shann told the court.
Mr Silbert said, in sentencing O'Neill, Justice Elizabeth Hollingworth should take into consideration the planning that preceded the fire at the flat.
He said two candle holders had been taken from the couple's farm.
"The fire was clearly pre-meditated," Mr Silbert said.
Justice Hollingworth will sentence O'Neill early next year on a date to be set.
