Beau Lamarre-Condon sent a message to alleged murder victim Jesse Baird telling him he would not exist after their break-up.
He said he was intending to convey that he would not acknowledge Mr Baird in public after their split.
The former police officer said he never intended to cause Mr Baird physical harm.
Beau Lamarre-Condon has denied he intended to hurt Jesse Baird harm after their break-up months before the television presenter's alleged murder.
The former police officer has pleaded not guilty to murdering his former partner and Mr Baird's new boyfriend Luke Davies at a Paddington terrace home on February 19, 2024.
He maintains both men died during separate struggles over Mr Lamarre-Condon's police pistol.
He told the court he threw Mr Baird's phone off Tom Uglys Bridge days after the shootings.
"I obviously did it because I didn't want any evidence of Jesse's phone on me," he said.
After meeting around October 2022, the pair broke up once in April 2023 and again in November 2023.
He accepted that Mr Baird asked him to refrain from contacting him after their break-up.
The court has heard Mr Lamarre-Condon frequently asked his friends for advice on draft text messages he was intending to send to Mr Baird during their relationship.
