A GoFundMe page to raise funds for alternative treatment and “to alleviate some of the pressure and stress”, brought in more than £150,000.
A message on the page said: “Rachel fought an incredibly brave and relentless four-and-a-half year battle with triple negative breast cancer.
“She faced every challenge with strength, courage, and without complaint, giving everything she had for as long as she could.”
Carey’s club posted on Facebook: “Everyone at Dunfermline Athletic was hugely saddened to learn of the passing of Rachel Borthwick, partner of Pars player Graham Carey.
“Our thoughts are with Rachel’s family and friends at this devastating time.”