Friends of Cam's ex - Tina Ciccio - have gone to Facebook to question his motives.
One remarked the star left her around the start of September before his wedding to Jules on September 20..
One wrote on Facebook: "[Cameron] never told her why they broke up, she only found out when they started putting his ugly mug all through the magazines in prep for the show."
Another said, "It was heartbreaking for a friend of mine who found out [he dumped her for MAFS] a fortnight before the show went to air."
On Wednesday, Cameron told Daily Mail Australia: "I was single when I entered the experiment' and said any claims he wasn't are 'fabricated and categorically untrue."
He did not comment on Tina.
On MAFS, Cam said he'd been single "for six years" after splitting from the "love of my life" due to work.
Before his first vows, he remarked: "Now I know what my priorities are that I can give to a wife and a partner.""