The ex-wife of convicted murderer Paul Mulvihill has recounted a string of “terrifying” incidents following their marriage breakdown.

A former wife of convicted murderer Paul Mulvihill has claimed her ex-husband sent her a “goodbye and good luck” card with a bullet after their short-lived marriage broke down.

Celine Carroll also claimed Mulvihill hid under her bed when she came home one night and said: “I’m going to kill you” and on another occasion waved a rifle around her.

Ms Carroll started dating Mulvihill at a Brisbane teacher’s college in 1987 and the pair were married within two years.

But the union began to splinter in less than a year when Ms Carroll confronted her husband about her infidelity suspicions.

Ms Carroll told the NSW Supreme Court at Mulvihill’s murder sentencing hearing that he threatened to kill himself.

“I told him I wasn’t particularly happy with the relationship,” she said.

“His response was to pick up a cord from the television and put it in his mouth …”

On another occasion, Ms Carroll told her husband she was going away for a few days but instead hid under their bed and heard her newlywed call three different women.

Mulvihill, 46, has been found guilty of killing his colleague and lover Rachelle Yeo, 31, after the pair started an affair in 2011.

The court heard Mulvihill admitted to having serious affairs with two women he worked with and shorter, sexual relationships with others.

Ms Yeo moved to Sydney for a job promotion with Sanofi Pharmaceuticals.

The trial heard Mulvihill followed Ms Yeo into her North Curl Curl unit in Sydney’s north in July 2012, and stabbed her in the neck and chest.

Ms Carroll said she took out a domestic violence protection order against Mulvihill.

But defence barrister Kate Traill suggested there was never any bullet and her client was not violent.

Ms Carroll told the court her ex-husband once grabbed her around the throat at her secured apartment block.

On another occasion, when she returned home to her Brisbane duplex with a man in 1992, Mulvihill jumped out from under her bed and threatened to kill her.

Ms Carroll’s sister told the court she felt compelled to contact police about Mulvihill’s past after hearing he was linked to Ms Yeo’s murder.

Mulvihill held his head in his hands and sobbed in the dock when his sister, Donna Parker, gave evidence.

Ms Parker, who spent every day at her brother’s three-week murder trial, said Mulvihill told her when he and his wife broke up in 2012 and admitted there was another woman.

The hearing continues.