The Underbelly: A Tale of Two Cities star is currently undergoing treatment after checking into rehab earlier this month (Aug10) for the second time this year (10).
A day after he was admitted to the facility, the actress took out an apprehended violence order (AVO) against the star, alleging she was the victim of two "gravely serious" attacks by Newton while they were vacationing together in Rome, Italy.
But in a new interview, the troubled star's parents insist the holiday was a romantic getaway and their son proposed to Taylor during the trip.
His mother, Patti, tells Australian news show A Current Affair, "He kept ringing me from all parts of the world. Russia, London and then the last one, he said Rachael and he were in Italy - and I've just found out they were... engaged. He bought her a ring and... then everything went sour.
"His biggest problem is the fact that (his temper is) not a drug, it's not an alcohol problem as much as it's a mental health issue. He's always had a bit of a problem with his temper, even as a kid, but I do think it's accelerated. We don't know how to handle it."
Newton's father, Bert, told the show his son's bad behaviour stems from "his lifestyle in Sydney and getting in with the wrong people."
He adds, "I do love him and I do support him, but I don't support or condone any of the things that have happened. We should have seen the signs... but we didn't."
The full interview is due to air in Australia on Monday night (30Aug10).