Alana Odysseos, 32, was in the early stages of pregnancy with her third child when she was attacked at her home in Walthamstow early last July 22.
Shaine March, 45, of Rainsborough Avenue, Lewisham, had admitted manslaughter by diminished responsibility but denied murder.
On Friday, he dramatically changed his plea and admitted the murder of Ms Odysseos.
It came after it emerged in legal argument on Thursday that a defence expert due to give evidence in his trial no longer supported his diminished responsibility claim.
In light of the guilty plea, Mr Justice Murray discharged the jury and lifted reporting restrictions relating to March’s previous conviction for murder.
It can now be reported that March was aged 21 when he fatally stabbed a man in the neck at a McDonald’s restaurant in January 2000.
He was convicted of 17-year-old Andre Drummond’s murder at the Old Bailey on July 17 2000 and jailed for life.
Following his release on licence in early 2013, he was recalled to jail later that year after an assault on another partner in July and released again in February 2018.
He had been seeing Ms Odysseos for around four months before the killing.
Hours before, the couple had argued with about whether to abort their unborn child, with the victim heard to say: “I don’t want to kill my baby.”
Members of the public in Lynmouth Road rang 999 after finding Ms Odysseos outside her home wearing a nightie and dressing gown and clutching her right side.
Bleeding from multiple stab wounds to her body, she pointed at the defendant standing nearby and shouted: “Shaine stabbed me, he stabbed me. Help, help.”
March walked away and Ms Odysseos died on the ground outside her address despite the efforts of police and paramedics, jurors heard.
She had suffered stab wounds to her chest, stomach, pelvis, shoulders, buttocks, right arm, thighs and lower legs.
Before throwing his mobile phone in a drain, March recorded a voice note saying: “Mum, I just killed a woman, and I’m going back to jail.”
At 4.41am, staff at Creams Cafe in Walthamstow called 999 to report finding a man covered in blood who told them he had killed his wife and child.
Following his arrest, March allegedly told police: “I did it. I killed her Alana Odysseos. I killed her hahahaha.”
As he was put into a police van, he went on to asked to be put in jail “where I belong”, saying he was “scum” and deserved it.
The defendant later allegedly told a prison officer that he “saw red” and stabbed his girlfriend with a knife from the kitchen after arguing about a pair of his trainers.
While in handcuffs and accompanied by two officers, March kicked the head of a fellow detainee, knocking three of his teeth out, the court had heard.
Mr Justice Murray remanded March into custody to be sentenced on October 31.
The court heard the prosecution would asked the judge to consider imposing a whole life order.
Members of Ms Odysseos’s family had sat in court throughout the trial.
On Friday, they witnessed March shouting and swearing in the dock before he returned to court in the afternoon and entered his guilty plea, bringing the case to a dramatic halt on its seventh day.
The family thanked prosecutors and the Metropolitan Police team of investigators before leaving court.
Detective Inspector Aytac Necati, who led the investigation, said: “My thoughts remain with Alana’s family and friends, as well as her young daughter, their lives will never be the same after she was so brutally taken away from them.
“March is a cowardly individual who showed absolutely no remorse for Alana or her family. Today he has finally admitted murder and will rightly face the consequences of his actions.
“This case shows the devastating impact domestic abuse has on victim-survivors, families and communities. I urge anyone who experiences domestic abuse or controlling behaviour to report it to police, our officers will listen and will support you.”
