The move came as a result of a plea bargain that she didn't know about until the day of the man's sentencing hearing, when Crown counsel phoned her.
The woman, whose identity and location CBC News is protecting, said she helped convict her ex-boyfriend, Trevor Zayac, on weapons charges after telling officers investigating her assault complaint about a large cache of guns he kept in his home in Winnipeg's Elmwood neighbourhood.
"If the assault wasn't brought in, they would have nothing," she said. "I have to build my life from scratch, take therapy, have nightmares.
"Someone was able to plea bargain my assault off the table." she said. "Isn't there a moral and ethical line there?"
The woman said she was assaulted after the couple had an argument during a family party in Beausejour, Man.
Zayac punched her, kicked her and knocked her out with a vodka bottle in a trailer they had brought to sleep in, according to court documents.
That charge was stayed by the Crown.
"I thought I was going to die. I really did," she said. "I thought he was going to kill me."
"Nobody came to help me," she added.
She went to a neighbour's house and that man called Beausejour RCMP. An officer took her to hospital where she stayed for six hours.
She told police about the weapons Zayac had stashed because she wanted them to "be prepared."
"I didn't want anyone to get hurt," she said, adding that she told police Zayac had fantasized about a shootout with authorities.
Zayac is being sentenced on Thursday after he pleaded guilty to unsafe storage, possession of a prohibited weapon and failing to report a lost or stolen firearm. He originally faced more than 30 charges in connection with a massive collection of weapons stashed in his home, including semi-automatics, rifles and body armour.
He legally owned all but one of the guns, but many were improperly stored, with one fully-loaded pistol kept under his kitchen sink. He built many contraptions in hollowed-out furniture and collapsible picture frames that kept the weapons hidden.
He was previously convicted in 1998 for possessing a small collection of weapons, including pipe bombs. He was given probation for those charges.
Feels ‘revictimized' by plea deal
The woman says she feels "revictimized" by the plea deal and can't understand how serious charges can be wiped away.
"That's the frustration that victims really feel in this country," said Heidi Illingworth, executive director of the Canadian Resource Centre for Victims of Crime.
"In this case, you're speaking about the woman who was assaulted, someone has uttered threats against her," she said. "So to have the system add another injury upon her can almost be worse than the first injury that she suffered."
Illingworth's group wants to see more Crown prosecutors be required to explain their decision-making processes to victims, especially when it comes to plea bargaining.
"Many have been seriously harmed and traumatized by the actions of another person, and they need to understand why the Crown has made a decision that they have," she said.
Michael Desautels, the prosecutor in the case, sent the woman a letter on Jan. 7, following the initial phone call.
"The standard for prosecuting any accused is whether or not there is a reasonable likelihood of conviction," he wrote.
He also wrote, "We take responsibility for the lack of timeliness of our communication of the actual disposition to you," adding that he decided to tell her in the new year.
In his letter, Desautels said the assault and uttering threats charges "were not strong" and the strongest case was the weapons-related case.
"We're not going to get into an exhaustive listing of the reasons for the plea bargain beyond what we've set out to you in our phone call and our previous letter," he stated in a follow-up email he sent the woman a few days later.
The Crown is seeking 2½ years for Zayac while defence attorney Martin Glazer has requested time served and a conditional sentence in the community.
The woman, who is now in hiding, says the justice system failed her and she fears that Zayac may hurt her when he gets out.
"It's like I was used as a pawn," she said. "I think he is definitely going to be seeking revenge."