In a surprising courtroom development, a Sydney man has admitted to killing his partner in a jealous rage.

The victim’s family broke down in tears on Monday as Charles Wheeliker pleaded guilty to second-degree murder in the strangling death of Troy Johnston.

Johnston’s family says while they are relieved to be spared the pain of a trial, nothing can bring back the 35-year-old father of two little girls.

“Troy was a very respectful man. He was very loving,” says Johnston’s cousin, Krystal Denny. “He loved his family, was very close with all of his friends. He’d do anything for anybody. I really don’t feel this should have happened to him and I’m satisfied that he’s (Wheeliker) going to spend probably his whole life in prison.”

Wheeliker showed little emotion as he pleaded guilty to second-degree murder.

The court heard Wheeliker and Johnston had been in a relationship for three years and that they had shared the Sydney apartment where Johnston was found dead on Aug. 17, 2012.

Police were called to the five-unit apartment complex on Townsend Street just before midnight. When they arrived on the scene, they found Johnston’s body in one of the units upstairs.

“There was an argument that evening and at the time of the argument, they were both under the influence of alcohol and drugs,” says Crown attorney Diane McGrath. “The argument became physical at which time Mr. Johnston was strangled with a belt.”

According to an agreed statement of facts, the argument started when Wheeliker accused Johnston of staying in touch with an old girlfriend that he had been texting throughout the night.

The court heard that as Wheeliker tightened the belt around Johnston’s neck, his phone continued to buzz with incoming texts.

According to the statement, Wheeliker told a neighbour he had returned home to find Johnston unconscious.

He was arrested once officers arrived on scene and gave a full confession the following day.

A sentencing hearing is set to begin next month.

With files from CTV Atlantic's Ryan MacDonald