With a history of violent outbursts, it seemed only a matter of time before Sydney man Christopher John Anderson would snap again.But few could have imagined the horrific and bloody act the 41-year-old would carry out at a Maroubra unit in the early hours of August 3, 2013.

Anderson was jailed for a minimum of nine-and-a-half years on Friday for fatally stabbing his pregnant girlfriend Allira Green through the heart with a kitchen knife during an altercation at a friend’s apartment.

His violent past was detailed during his sentence hearing at the Supreme Court in Sydney.

At the time of the deadly attack, Anderson had been on bail for a vicious assault on an ex-girlfriend’s father, which left the victim with a broken arm.

And in July 2011 he was prosecuted for giving his ex-girlfriend a swollen eye.

Also, the court heard, between 2001 and 2007 Anderson was convicted of three other serious attacks – including one which left the victim with a fractured skull.

But the violence paled in comparison to his attack on 23-year-old Ms Green, who was five to six months’ pregnant with his child.

Justice Peter Hall said an angry and aggressive Anderson had forced himself into a Maroubra unit where Ms Green and two other women were, and said words to the effect of, ‘I’m going to get you’.

The confrontation followed days of heated text message exchanges in which Anderson had complained of Ms Green’s drug use, and she rebuffed his attempts to reconcile.

When Anderson grabbed Ms Green’s friend and pushed her over, Ms Green took a knife from the kitchen and moved towards her boyfriend.

During the ensuing struggle, he took the knife and stabbed her in the chest.

The knife pierced 15cm into Ms Green’s chest wall and upper heart and she was dead by the time ambulance officers arrived.

Anderson later told a friend he’d taken the drugs ice and Xanax before the attack.

Ms Green had also taken ice, as well as cannabis, on the night, the court heard.

Anderson pleaded guilty to manslaughter of the basis of excessive self defence at the start of his second murder trial last November after the first jury failed to reach a verdict.

He was sentenced on Friday to 12 years and nine months’ in prison, with no parole for at least nine-and-a-half years.

Justice Hall rejected defence claims Ms Green had provoked the stabbing, saying she’d grabbed the knife in self defence and that Anderson’s response was ‘extreme and grossly excessive’.

Outside court, Ms Green’s tearful mother Nardia said she was happy with the sentence, but stepfather Charlie Dargan called for tougher domestic violence laws.

‘I still say we’ve got the weakest justice system in the world,’ he told reporters.