A Royal Marine was stabbed through the heart by his ex-lover after she "lashed out" with a knife she kept under her bed, a court has heard.
Mr Swallow died from massive internal and external bleeding
Danielle Bradley, 26, of Crawshaw Close, Plymouth, was giving evidence at her trial at Exeter Crown Court.
Ms Bradley denies murdering 23-year-old James Swallow, from Leeds, but has pleaded guilty to his manslaughter.
The waitress told the jury she picked up the knife after Mr Swallow called her by the name of his new girlfriend.
The single mother said the stabbing happened in her bedroom when Mr Swallow intervened as she tried to self-harm.
She said she did not intend to kill the Royal Marine or cause him serious bodily harm.
Mr Swallow was killed on 30 November last year, three months after he and Ms Bradley had split up. He then had a new girlfriend from his home town of Leeds, whose name was Vicky.
The court heard Ms Bradley had met Mr Swallow when she was on a night out in Plymouth with some friends. He had gone home with her in a taxi after she told him she was finding it hard to cope without him.
Ms Bradley told the jury Mr Swallow called her "Vick" when they were lying on the bed talking and looking at photographs of a holiday they had been on together. She said she did not know who "Vick" was, but guessed.
"I said if you are going to call me that you might as well go back to her," Ms Bradley told the court.
She said as Mr Swallow phoned for a taxi to take him back to Bickleigh Barracks, she was sobbing and picked up the knife she thought was under her bed.
She said: "I started to have that feeling I get before I harm myself. It builds up. I reached for the knife to hurt myself.
"I remember screaming and shouting at James. I asked him to leave so I could get on with it.
"James reached towards me and grabbed at my arm. I felt a dull sensation. Then James said 'Dan, you have stabbed me in the heart'.
"I think it was just a reaction to him grabbing my arm. I lashed out to push him away."
Earlier in the trial, the court heard Mr Swallow died from massive internal and external bleeding when up to 18cm of a 20cm knife blade went into his chest.
The case continues.