The man, a 43-year-old Hamilton glazier, was yesterday in a stable condition in Waikato Hospital with family members at his bedside. The incident happened just before midday on Sunday.
The woman, who is having a psychiatric assessment, fled the scene and drove her car over a cliff and into the Waikato River but was hauled to safety.
A friend of the injured man, who asked not to be named, said he was a gentle soul who was shocked and devastated by what had happened.
The friend said the couple had been in a volatile on-and-off relationship for about four years.
The friend said the man sought help for the woman's behaviour in the past without success.
"He's been struggling for quite a while with it. He's quite a big man but he's a gentle man - he hasn't got a violent bone in his body. He told me he was just trying to help her."
The friend said he often sounded scared or shaken on the phone and he had become isolated from his friends and family.
His family and friends told him to leave "but obviously she had some kind of emotional hold on him".
"Because he is quite a gentle, kind of caring man he was just trying to do right by her."
The woman was discharged from Waikato Hospital on Sunday with minor injuries.
The Herald understands she was admitted to the Henry Rongomau Bennett Centre for psychiatric assessment.
Detective Senior Sergeant Ross Patterson of Hamilton CIB said any matters in relation to historic events leading up to Sunday's incident would be looked into.
The woman has not been interviewed but police hoped to speak with her "once her situation has been clarified".
Any further action would be decided after establishing the facts.
- James Ihaka
