The attack occurred in Wanganui on September 11 when the two were visiting Rangi's parents.
The victim's attempt to take a drink from Rangi's hand during a drinking session angered him, so he punched her.
She instinctively hit him back, triggering the assault in which he punched her at least a dozen times in the face.
To stop her screaming, he also removed her scarf and stuffed it into her mouth, while at the same time blocking her nose.
Unable to overpower him and unable to breathe, she bit his finger. In retaliation, he bit both her arms, then her cheek.
The bite to her face was done with such force skin was left hanging from her face.
The attack ended and he tried to apologise, but she spent the night sleeping in the car outside the house, before leaving the next morning to drive back to Hastings.
"There is no doubt from the probation officer's report, Mr Rangi, that you have made your difficulties with alcohol," Judge Rea said.
"It's daunting to see that over the last few years you have numerous assault convictions, many for assaulting women and you have served terms of imprisonment quite recently for physical assaults on the same victim.
"Your partner puts it down to the fact that you black out and can't remember what you do, and when you finally come to... You are very apologetic and wish it hadn't happened.
"Your violence seems to be getting worse and worse. This was a sustained and brutal attack on another person."
He received an uplift in his sentence for his criminal history, but an early guilty plea earned a 25 per cent reduction.
It was also his first three strikes offence.