"If anyone was going to do it, she was going to do it," he told the Daily Mirror.
"You watch programmes like CSI on TV and think, 'Christ, that's an evil woman'. But that was her. Everything had to be about her."
Although he remained angry with his father for the way he treated his children, he believed his mother had led her husband astray.
"My father was a good man, a soft-hearted man. But she was a conniving b****. She controlled him but he loved her to pieces. That's what's cut me up the most. Your parents being murdered by anyone is bad enough, but by your mother ... If I could afford to go to his funeral I would. I would be on a plane tomorrow. I've got a lot of demons to put to bed. But I am just overwhelmed at the moment."
He had told his wife, but not his two sons, Steve told the Daily Mirror. "I don't know how to."
Steve moved to New Zealand from South Wales with his parents and three siblings in the 1960s. His youngest sister was born after their arrival.
But the couple later ditched their kids and returned to the UK, he said.
"They dropped us off somewhere and never came back to pick us up. They said they were going to come back the next weekend."
Social services stepped in but the abandonment hit the children hard. Steve's brother took his own life about 15 years ago, having never got over it.
A brief reconciliation occurred when the couple returned to New Zealand in the mid-1980s.
"They came back when I was 23 and tried to make amends and it hit the news here. We lived in Australia for a while when we were kids and their story was that because he was an accountant, he had ripped someone off and came to New Zealand with the money.
"My mother was a cabaret performer and they said they went back to Australia for that. But he got arrested and she stayed out there with him and things just escalated from there. At the time, as a young man, I wanted a family so I let it go."
The reunion was brief -- his parents took him to a budget hotel in Auckland, promised to return in a couple of days and never returned, Steve Sabine said.
"People asked why we took them back but we said that all our lives all we wanted was to have a mother and a father. We had never had that. But it only lasted a few weeks. They were worried they were going to get thrown in jail, that's why they bolted. It was always all about them. People would ask about my parents and I would say they were dead."
He still wished he could have his father back. "If I could have any way to get my dad back I would, even though he did some horrible things and we had a miserable childhood. We have been treated like rubbish. I could never forgive him for what he did but I still believe he was manipulated and he fell in love with an evil woman.
"That was his biggest crime."