Crown counsel Rebecca Guthrie said it was the eighth time since 2011 Brown had been convicted as a result of separate incidents of either violence or breaches of a protection order against the woman.
The court heard Brown and his partner, who were separated at the time, had been in a relationship for 15 years with four children together.
Brown was only 12 days out of prison after a two-month sentence for breaching the order against him and dangerous driving.
He loitered outside the property where the woman was staying, then broke in after the usual occupant left for work.
Unable to find the woman as she had hidden, he left.
She emerged, thinking it was safe, but Brown returned. She tried to hide again but Brown found her, pulled her by the hair to the ground, verbally abused and repeatedly stamped on her.
He dragged her dazed, nauseated and badly bruised outside. She screamed for help and tried to flee but he grabbed her and threw her in his van. He drove to a secluded part of Whakamahi Beach where the beating continued.
Judge Down said photos of the woman's injuries were shocking. She was black and blue from extensive bruising to her head, face and body. Her eyes were closed.
It was hard to imagine a more severe assault and only sheer luck that she was not more permanently injured, the judge said.
Judge Down said the lead offence was the kidnapping charge, which carried a 14-year maximum. He rejected counsel Nicola Wright's submission it was an unfortunate part of the factual matrix and that the injuring charge should dominate.
Reaching a final sentence, the judge started with what he called a "modest" four years imprisonment for the kidnapping. A year each were added for the burglary and breach charges.
Brown was clearly not learning from the sentences imposed on him previously, the judge said. A further six months was added for previous offending.
Having established a start point of six and a half years, Judge Down allowed 20 per cent discount for Brown's guilty pleas... 5 per cent of that for matters pleaded on his behalf by Mrs Wright and because the complainant had at least been spared the need to give evidence, the judge said.
But he refused to give any discount for remorse beyond what was implicit in the plea.
A letter Brown wrote to the court "simply didn't do it", the judge said. Brown's remorse was not genuine. It was clear in a pre-sentence report and his claims through counsel that he constantly sought to minimise his offending.
In her victim statement, the woman said the assault was Brown's worst yet.
It was "that bad that I thought I would die. I remember telling him to just let me die."
She still had nightmares and found it difficult to sleep. She was convinced he would exact revenge on her on his release and that he would kill her.
She intended to leave the country with their children so he could not find them.
