In his story, Whibley claims that Greig Nori, the band’s initial manager, began grooming and assaulting him sexually when he was a teenager.
The singer claims in an interview with the Los Angeles Times that he concealed the negative aspects of the relationship from his bandmates for a long time.
Whibley’s claims have been referred to as “false” by Mr Nori.
Since their 1996 formation, the multi-award winning punk band Sum 41 has sold over 15 million albums worldwide.
Walking Disaster: My Life Through Heaven and Hell, Whibley’s memoir, was released on Tuesday and chronicles the highs and lows of the band’s early career.
Mr. Nori, who was the leader of a well-known Canadian indie band in his 30s at the time, contributed to its start. After a show, he got to know Whibley and started mentoring him.
Mr. Nori went on to manage the young band.
Whibley claimed that one evening, while high on ecstasy at the party, Mr. Nori unexpectedly and “passionately” kissed him in a restroom, startling and perplexing the then-18-year-old.
He claims that over the course of around four years, Mr. Nori forced him into an unwelcome sexual relationship.
“Greig kept pushing for things to happen when we were together,” he writes in his memoir, according to the Toronto Star.