The daughter of the Nobel prize winner Alice Munro, Andrea Robin Skinner, has alleged that her stepfather sexually abused her as a child, and that her mother stayed with him even after he admitted to the abuse.

Skinner revealed the allegations in an essay and a news article in Canada’s Toronto Star on the weekend, writing about how her stepfather, Gerald Fremlin, began sexually assaulting her in 1976 when she was nine years old and he was in his 50s.

She alleged that Fremlin got into a bed where she was sleeping at her mother’s home in Clinton, Ontario, and sexually assaulted her. Skinner told her father, James Munro, who she says did not tell Munro.

Over the following years, Skinner says Fremlin propositioned her, exposed himself to her, and “told me about the little girls in the neighbourhood he liked”. Skinner said he stopped assaulting her when she became a teenager, but she developed bulimia, insomnia and migraines, which she attributed to the abuse.

In 2005, Skinner went to the police. Fremlin, then 80, was charged with indecent assault against Skinner and pleaded guilty. He received a suspended sentence and two years’ probation. Munro stayed with Fremlin until he died in 2013.

Munro, who was regarded as one of the greatest short-story writers of all time and won the Nobel prize for literature in 2013, died last month at the age of 92.

Skinner wrote that she first told her mother about the abuse in 1992, when she was in her 20s, writing her mother a letter after Munro voiced sympathy for a character in a story who was sexually abused by her stepfather.

However, Skinner said that Munro “reacted exactly as I had feared she would, as if she had learned of an infidelity”.

Munro temporarily left Fremlin, who admitted in letters to the abuse but blamed it on Skinner. “If the worst comes to worst I intend to go public,” he wrote, according to Skinner. “I will make available for publication a number of photographs, notably some taken at my cabin near Ottawa which are extremely eloquent … one of Andrea in my underwear shorts.”

“She said that she had been ‘told too late,’ … she loved him too much, and that our misogynistic culture was to blame if I expected her to deny her own needs, sacrifice for her children and make up for the failings of men,” Skinner wrote. “She was adamant that whatever had happened was between me and my stepfather. It had nothing to do with her.

“I … was overwhelmed by her sense of injury to herself. She believed my father had made us keep the secret in order to humiliate her. She then told me about other children Fremlin had ‘friendships’ with, emphasising her own sense that she, personally, had been betrayed. Did she realise she was speaking to a victim and that I was her child? If she did, I couldn’t feel it.”

Skinner distanced herself from her family in 2002, after telling Munro she would not allow Fremlin near her children. But after reading an interview where Munro spoke positively about her marriage, Skinner took Fremlin’s letters to the police in 2005.

“He described my nine-year-old self as a ‘homewrecker,’” she wrote, adding that he accused her of invading his bedroom “for sexual adventure”.

“The silence continued” even after Fremlin’s death, Skinner wrote, because of her mother’s fame.

“I also wanted this story, my story, to become part of the stories people tell about my mother,” she wrote. “I never wanted to see another interview, biography or event that didn’t wrestle with the reality of what had happened to me, and with the fact that my mother, confronted with the truth of what had happened, chose to stay with, and protect, my abuser.”

• In the UK, the NSPCC offers support to children on 0800 1111, and adults concerned about a child on 0808 800 5000. The National Association for People Abused in Childhood (Napac) offers support for adult survivors on 0808 801 0331. In the US, call or text the Childhelp abuse hotline on 800-422-4453. In Australia, children, young adults, parents and teachers can contact the Kids Helpline on 1800 55 1800, or Bravehearts on 1800 272 831, and adult survivors can contact Blue Knot Foundation on 1300 657 380. Other sources of help can be found at Child Helplines International