The former partner of Paul Retallick was attacked by him two days before his beaten body was found in Langport, Bristol Crown Court heard.
Heidi McGinty, 26, now of Ilminster, told a jury on Tuesday that Paul Retallick, 35, left her with bruises on her arms and legs after an attack on Friday, September 14, last year.
The mother-of-three told how her four-year relationship with the Mr Retallick became violent just weeks after they first became a couple.
The abuse did not happen often to begin with but became worse when she moved to Iris Way, in Langport, more than two years before Mr Retallick’s death, she said.
Mr Retallick, formerly of Barwick, near Yeovil, was found dead at Miss McGinty’s former Langport home on Sunday, September 16, last year.
Miss McGinty’s father Michael Frank McGinty, 55, and her brother Lee McGinty, 25, both of Peony Road, Langport, deny his murder.
Police were aware of the couple’s abusive relationship, which had resulted in a court appearance, the court was told.
The court heard how the mother-of-three suffered severe bruising on her body as a result of the attacks and was left with a broken nose after an incident in March 2012.
Miss McGinty – who had one child with Mr Retallick – said he “terrorised” her family prior to his death.
Giving evidence to the trial, she told how he sent her family threatening messages and attacked her father in 2011.
Although her family had discovered Mr Retallick was beating her prior to his attack on Michael McGinty, it was this event which led to the eventual deterioration of Mr Retallick’s relationship with her family, she said.
She added: “He was just disgusting. I was scared. He was texting everyone, my mum, my dad, my brother’s girlfriend.”
She described obscene claims by Mr Retallick that he was having sex with her mum and her brother’s girlfriend.
She said the boasts were “sick.”
Miss McGinty said: “Paul terrorised my family. He just wouldn’t leave them alone. My dad used to have to sleep with his windows open because Paul was always threatening them.
“He was constantly doing over their cars and threatening to get them on their way to work. I was worried about my family.”
Miss McGinty said her dad “wasn’t the same person any more” after Mr Retallick attacked him.
She added: “He lost all confidence, it ruined him.”
Miss McGinty said the incident – during which her father suffered a punctured lung and broken ribs – angered her whole family.
She said Mr Retallick “walked free” from court afterwards.
She added: “Lee used to sit in the background. He never rose to it. He was angry. Everyone was angry.”
Miss McGinty’s parents moved from Yeovil to Langport a couple of months before Mr Retallick’s death, the court heard.
The trial continues.