Jessica Silva was suffering from battered wife syndrome and believed her estranged partner had killed before and was going to kill again when she stabbed him to death outside her family home.
These elements of her case make it exceptional and should mean she should not go to prison, her barrister says.
Silva stabbed James Polkinghorne up to five times on Mother's Day in 2012 after he arrived outside her Marrickville home in Sydney fuelled on the drug "ice".
The 25-year-old pleaded not guilty to his murder on the basis of self-defence but after five days of deliberation, a jury found her guilty of the lesser charge of manslaughter last year.
At her sentence hearing on Friday, her barrister Gregory Scragg called for a good behaviour bond or a suspended sentence.
In mounting his case, Mr Scragg said Silva had been abused by the 28-year-old for years. It meant that by Mother's Day 2012 she was suffering from "chronic and complex" post traumatic stress disorder - particularly "battered wife syndrome".
"She believed he was omnipotent, omnipresent and completely controlling," he told the Supreme Court.
Leading up to his death, Mr Polkinghorne had increased his use of "ice", becoming more aggressive and paranoid.
Silva also believed he had shot and killed Nikolas Argiropoulos, whose body was found in a park in Birchgrove in Sydney's inner-west on March 22, the court heard.
And so following a day in which he had sent threatening texts - telling her he was going to "cave" her face in - Mr Scragg said she believed he was coming to kill her.
"She went outside scared and crying because she thought if he is going to kill someone let it be me and not any members of my family," he said.
"He was on a mission of self-destruction."
Crown prosecutor Eric Balodis disagreed, saying that at the very least Silva meant to cause him grievous harm and a custodial sentence would be the most "appropriate" course of action.
Earlier in the proceedings, Silva cried as Mr Polkinghorne's sister Anne-Marie Spice said in a victim impact statement "There is not hate ... just sadness for both our families".
Polkinghorne's mother Arosja Gouveia said the news of her second youngest child's death turned Mother's Day into the worst someone could ever experience.
Silva, who is on bail, will be sentenced on March 6.
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