New Zealander Shane Richardson, 29, and Englishman Owen Jenner, 21, were both fatally injured in the 11-bike pile-up on the first lap of the race at Oulton Park in northwest England on Monday.
A third rider Tom Tunstall, 47, remains in hospital with a broken neck.
For Hannah James, Richardson's girlfriend and mother of his two children, there was the additional devastation of history repeating itself.
Her previous companion, ex-soldier Billy Redmayne, who had done three tours of duty in Afghanistan, died after crashing in a road race in Scarborough, northern England, in 2016.
"It's just unthinkable that this has happened again for her," Leanne Harper, who lost her own partner Dan Kneen in the 2018 Isle of Man TT motorbike race, told Britain's Daily Telegraph newspaper.
But she added that some people who suffered the death of loved ones in motorcycle races had not turned their backs on the sport.
"It happened with Hannah and Billy, but she still found love again inside the paddock so it shows that we don't hate the sport - we've got that passion for it and they (the riders) are doing what they love to do," Harper said.
"Everyone knows the risks at the end of the day. They just love it that much... It's not that we hate the sport, it's just sometimes it can end really tragically, which is the downside."
Police and officials have launched investigations into the circumstances of the crash.