Shane Gilmer, 30, died after his next-door neighbour Anthony Lawrence, 55, broke into his home in Southburn, East Yorkshire, and shot him with a crossbow bolt that passed through his right arm and damaged his liver, kidney and spine.
Laura Sugden, who was 20 weeks pregnant at the time of the attack in January 2018, was shot in the head but she survived.
After the inquest into her partner’s death, she began campaigning for the government to introduce tighter regulations and she is now urging people to sign her petition, which has more than 38,000 signatures.
The 30-year-old wants to see the "absolutely lethal" weapon restricted in the same way as firearms, to ensure people must undergo stringent police checks to legally obtain one.
Ms Sugden said: “You only have to read about how damaged Shane’s body was by one bolt - it caused his death. Surely it’s common sense that they need to be regulated.
“To me, one death is enough for the law to be changed. “
Professor Paul Marks, Senior Coroner for East Riding of Yorkshire, wrote to Home Secretary Priti Patel after the inquest and said the government should look at regulating the possession of crossbows in the UK.
In his letter, the coroner said “action should be taken to prevent future deaths” and pointed out that unlike firearms, there is “no on-going control, record or licensing requirement” for these weapons, which can be bought legally by anyone over the age of 18 in the UK.
Ms Sugden believes Shane’s death could have been prevented, if his killer had been required to undergo police checks and obtain a licence for a crossbow.
“There were three crossbows purchased and still now - three and a bit years later - nobody is aware of where they came from," she said.
“There's no record of them being bought, which suggests to me that there's no real record of anybody buying them. Nobody knows how many are coming into the country.”
She added: “Not only does this story highlight that something horrific happened, it also highlights to individuals - criminals - that these things are so easily accessible.
“If you can have a crossbow, why can't you have a shotgun without a licence? It just doesn’t make any sense.”
Ms Sudgen said she is now campaigning in Shane’s memory and raising their daughter Ella, who will turn three in June.
She said: “He would have done exactly the same thing. He was always helping other people and this will be the last thing I can do for him.”
A Home Office spokesman said crossbows “are subject to strict controls” and legislation is in place “to deal with those who use them as a weapon”.
He added: “We keep the legislation on bladed articles and offensive weapons, including crossbows, under review.”
But Gemma Vine, the solicitor representing Ms Sugden, said the current legislation only prevents the sale or ownership of a crossbow for under 18s.
She added: “The only other legislation that is currently in place only kicks in after there has been an incident involving a crossbow. The law is currently reactive, rather than preventative, meaning that similar murders and serious injuries are more likely to occur again.
“Incidents involving crossbows are more common than you might imagine and are not isolated events. Our research has revealed that attacks are on the increase, and the law needs to be changed to protect others from the same fate as Shane.
“Crossbow fire is extremely powerful, they have a similar effective range to a shotgun but offer the accuracy of a rifle.
“The arrow that struck Shane was propelled at such force that it fractured the bone in his arm and passed into his side through vital organs before embedding itself in his spine.
“Shane died in the most horrific and cruel way, and we want to try and prevent it from happening to others.”
The five-day inquest heard that Mr Lawrence, who lived next door to his victims, altered the crossbow darts to make them more lethal before he carried out a “carefully planned, premeditated” attack on January 12.
Ms Sugden was shot in the head and when she removed the bolt, her attacker pushed it into her neck. But she managed to escape and run to a nearby house.
Lawrence fled and was found dead in a camper van that was parked in a lay-by near Scarborough in North Yorkshire on January 14 in 2018.