He referred several times to the victim being dead, said he would have her bleeding on their son before police arrived, and that he would stitch their son into her stomach.
In court yesterday, defence lawyer Frank Minehan said Peachey has been attending a stopping violence course and would be willing to offer an emotional harm payment to the victim.
Mr Minehan said Peachey is employed and living with his parents, who are supportive of him.
He said Peachey had shown a degree of remorse.
Judge Jill Moss said she was unsure whether Peachey had worked out that his plan to try and hold his former partner in the relationship, by making her fearful, was "a really dumb thing".
"You don't want to teach your baby that this is the way to live your life. It's all about what the future for your baby looks like," Judge Moss said.
Judge Moss ordered Peachey pay the victim an emotional harm reparation of $300 and attend any programmes directed by probation.
On a charge of wilful damage to the victim's car Peachey was convicted and discharged.
