"She struggled to breathe as the defendant was squeezing hard," Judge David Cameron said.
The victim's friend tried to help her, but was grabbed by the arm and pushed into the wall, leaving bruises on her bicep.
Millar then grabbed the hood of his partner's sweatshirt and pulled it up, choking her. He throttled her again, and she managed to break free and dial 111, handing the phone to her friend.
The partner grabbed her clothes that were scattered around the floor, picked up her cat, and walked out. When he saw his partner talking to police on her cellphone, Millar chased the two victims down the street, took her cat and threatened to kill it and her.
He then knocked her in her eye.
"He was located walking back to the address, still holding the cat," Judge Cameron said.
The offences had been committed while he was under supervision for a previous assault on the same partner, which occurred on September 13. He also behaved threateningly towards her on October 9.
Police prosecutor Sergeant Stephen Butler said the victim had made a statement to the effect she was "terrified" Millar would hurt her again if allowed out on bail.
Millar was sentenced to eight months' imprisonment and ordered to attend alcohol and drug counselling and family violence counselling on release.