Chef Dixon Tauteka, 34, and the psychologist had been drinking heavily when they began arguing about her rumoured affair with an inmate at a Victorian prison, defence lawyer Stephanie Keogh-Barnes told the County Court on Tuesday.

During the heated argument Tauteka, a former kickboxing champion who once represented Victoria, tossed the psychologist's clothes on to the bed and set it alight using kerosene.

He left the burning house in a bayside suburb, after packing a bag with his own belongings and taking the dog, in the psychologist's mother's car.

The fire caused more than $288,000 damage to the house, which had to be demolished.

The psychologist lost everything in the blaze except for the clothes she was wearing on the night.

Tauteka pleaded guilty to one count of arson, one count of theft, two counts of breaching a family violence intervention order, and two counts of breaching his bail conditions by contacting the psychologist.

Crown prosecutor Luisa Di Pietrantonio said the couple lived together at the psychologist's mother's home for just over two months when they argued about their relationship on May 24 last year and the psychologist went to buy more alcohol.

Ms Di Pietrantonio said Tauteka later told police he drove to a park, crept to the top of a slide and closed his eyes for an hour to try to get some rest as he was emotionally distraught after setting fire to the house.

Ms Keogh-Barnes said Tauteka, who moved from New Zealand to Melbourne with his family when he was six, had a cannabis dependence disorder, low to average intelligence, and no history of violent behaviour.

She said Tauteka's offending was out of character and took place in an atmosphere of conflict, anger and jealousy.

The defence lawyer claimed this was not a case of unrequited love, and that since Tauteka's arrest  both parties were keen to continue the relationship.

Judge Philip Misso will sentence Tauteka at a later date.