Mitchell Pearce's inappropriate text messages to a female employee at the Newcastle Knights were discovered by her boyfriend just days before the NRL star's wedding.
Pearce, 31, and his fiancee, Kristin Scott, were forced to call off their big day after the flirty messages were exposed.
According to The Daily Telegraph, the female employee is in a long-term relationship with a man who is close friends with several members of the Knights playing group, including forward Lachlan Fitzgibbon.
He was the one who found Pearce's texts, creating a snowball that has not only rocked the former NSW Origin star's personal life but also reportedly caused a rift at his footy club.
The Daily Telegraph reports Newcastle coach Adam O'Brien is "poised to take the captaincy" from the 297-game halfback.
The Knights return to training on Monday where the issue is expected to be thrashed out.
It could even impact Pearce's long-term future at the club, given his current $1 million a season contract ends after the 2021 season. The Telegraph reports he was offered a two-year extension that halved his salary before this latest scandal.
The wedding bombshell came just a week after Pearce had told the Newcastle News how excited he was to be marrying Scott.
"It will be the best time of our life and I can't wait," he said.
Pearce and Scott began dating early last year and went public with their relationship last May.
Many at the Knights credited Scott with helping Pearce grow from a trouble-plagued ratbag to a mature leader.
They travelled the world together, holidaying in places like Bali and New York, before she moved to be with him in Newcastle.
"She is an awesome girl," Pearce told The Daily Telegraph in February. "I'm feeling very settled in my life.
"She's a beautiful girl and I'm looking forward to sharing our future together.
"There is stability. We get along great and we're best friends. It's only been a year but we've spoken about our future together and we're excited about it."
In April this year Pearce popped the question, describing their engagement as "the best day of my life".
Scott was ecstatic too. "Life has just fallen into place," she wrote after accepting his proposal. "I cannot wait to be your wife."
The messages Pearce allegedly sent to the young woman were described as "flirty".
A source close to the Knights said: "There's been nothing physical, just stupidity on Mitchell's behalf with a young girl who works at the club. A lot of people are upset about it."
Knights media boss Frank Barrett told the Telegraph the club is "aware of the issue but it's a private matter that stays between the two individuals".
Pearce also hit back when contacted by the paper, saying the pair hadn't cancelled but rather postponed their nuptials.
"It's Covid mate … and it's private," he said. "We're sorting things out. It's a really stressful time for us. It's our business, no-one else's."