Michael Kelly, 41, turned on the woman at the flat in Glasgow’s Springburn on August 18 2023.
Enraged Kelly smashed her head off a door frame before he got on top of her and put his hands around her neck.
Kelly, of the city’s Royston, repeatedly told his victim during the horror ordeal that he was going to kill her.
Kelly pleaded guilty this week at Glasgow Sheriff Court to assaulting the woman to her injury.
He also admitted behaving in a threatening or abusive manner towards her.
The court heard that the pair had been together for two years at the time of the attack.
Kelly had been out drinking heavily that day and went to her home at 2.30am.
Prosecutor Jacky Wall said: “She asked Kelly to leave due to his intoxicated state, however, he refused.
“He began acting belligerently towards her and she asked him to leave again at 3.40am.
“Kelly shouted at her that he was going to kill her.”
Kelly grabbed his guitar and smashed it against a wall before he turned his attention towards the woman.
Miss Wall added: “He grabbed her by the hair and threw her to the floor then repeatedly struck her head off the door frame causing a wound to her ear and head.
“He dragged her by the wrist and threw her on a bed, got on top of her and placed his hands around her neck
“He shouted that he was going to kill her and asked if she wanted to see her children again.”
Kelly then dragged the woman to the bathroom where he rubbed her head forcefully in an attempt to wipe blood.
She made attempts to speak to 999 but was incoherent at the time.
Police later attended and found the woman in a “distressed” state with blood on her face.
Kelly had fled the scene by this point.
She was taken to hospital where she was found to have suffered injuries to her head and torso.
There was dry blood around her ear and wounds to her neck and elbow.
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Kelly was later traced by officers and stated: “I smashed my guitar but I didn’t threaten to kill her, why would I threaten to kill my girlfriend? I love her.
“I never grabbed her hair and all that.”
Sentence was deferred pending background reports until next month by Sheriff Iain Fleming who continued Kelly’s remand in custody meantime.