Never-before-seen Sylvia Plath letters paint a disturbing secret about her marriage.

Letters have come to light that suggest a new dark side to the Sylvia Plath/Ted Hughes relationship. Plath claims in the letters that Hughes beat her two days before she miscarried their second child – and that he told her he wished she was dead.

The relationship between the two poets is one of the most famous in literary history. Boston-born Plath showed her literary brilliance from childhood, having her first poem published at the age of eight. But her childhood was marred by tragedy. Her father Otto, a scientist, died after failing to seek medical treatment for diabetes.

Plath struggled with depression. In 1953, at the age of 20, she attempted suicide.

LISTEN: Sarah Ferguson and Andrew a former abuser talk about domestic violence in Australia.

After receiving electroconvulsive therapy and insulin shock treatment, under the care of Dr Ruth Beuscher, Plath returned to college. She won a Fulbright scholarship to study at the University of Cambridge. While at Cambridge, she read some poems in a magazine written by Hughes, a fellow student. Impressed, Plath went to a party in the hope of meeting him.

Four months later, they were married.

“We kept writing poems to each other,” Plath told the BBC in an interview. “Then it just grew out of that, I guess, a feeling that we both were writing so much and having such a fine time doing it, we decided that this should keep on.”

The couple moved to the US for several years. Plath had psychoanalysis sessions with Dr Beuscher. After Plath moved back to the UK with Hughes, she kept up a friendship with Beuscher.

Plath and Hughes’ first child, Frieda, was born in 1960. The same year, Plath published her first collection of poems, The Colossus.

Plath miscarried their second child in 1961. She wrote about it in several poems, including Parliament House Fields: “I suppose it’s pointless to think of you at all/Already your doll grip lets go.”

The following year, she gave birth to a son, Nicholas. But her relationship with Hughes was to last only a matter of months beyond the birth.

Plath and Hughes had rented their London flat to another poet couple, Assia and David Wevill. Hughes fell for Assia Wevill, later writing: “She sat there.../Slightly filthy with erotic mystery.../I saw the dreamer in her/Had fallen in love with me and she did not know it.”

Plath discovered Hughes was having an affair with Wevill. She left him, taking Frieda and Nicholas with her.

In a burst of creativity over the following months, Plath wrote many of her greatest poems. Her semi-autobiographical novel, The Bell Jar, was published under the pseudonym Victoria Lucas.

But her depression had returned, and she struggled with suicidal thoughts. Her doctor prescribed her antidepressants and arranged for a live-in nurse to help her with her children.

On the morning the nurse arrived, she found Plath dead inside her kitchen. She had left out milk and bread for Frieda and Nicholas who were sleeping in the next room.

It was February 1963, and Plath was just 30 years old.

Hughes and Wevill took over care of the children. But six years later, Wevill committed suicide using the same method as Plath. She also killed her four-year-old daughter with Hughes, Shura.

Plath’s supporters have long claimed Hughes was emotionally abusive and blamed him for her suicide. At poetry readings, he would sometimes be interrupted with shouts of “murderer”. The feminist poet Robin Morgan wrote a poem, The Arraignment, which begins, “I accuse/Ted Hughes…”

Hughes died in 1998. Plath and Hughes’ son Nicholas, a scientist, took his own life in 2009.

These newly discovered letters are likely to add weight to the argument that Hughes was abusive towards Plath.

The letters are believed to have been written by Plath to her therapist, Dr Beuscher, later Barnhouse. The last was written just a week before her death. They were in an archive held by scholar Harriet Rosenstein, which was recently offered for sale. The sellers say the letters introduce Plath’s voice “on the trauma of domestic abuse”, with descriptions of “physical abuse and psychological torture at the hands of her husband”.

Plath biographer Andrew Wilson says this could be the “the missing link”.

“These letters look as though they could fill certain gaps in our knowledge, and seem as though they can shed new light on the turbulent, controversial marriage between Plath and Hughes,” he tells The Guardian.

However, a statement released on behalf of Hughes’ widow Carol has challenged the contents of the letters.

“The claims allegedly made by Sylvia Plath in unpublished letters to her former psychiatrist, suggesting that she was beaten by her husband, Ted Hughes, days before she miscarried their second child are as absurd as they are shocking to anyone who knew Ted well,” it reads.

If this post brings up issues for you, or you just need someone to talk to, please call Lifeline on 131 114. You can also visit the Lifeline website here and the Beyond Blue website here. For 24-hour assistance please call the National National Sexual Assault, Domestic and Family Violence Counselling Service on 1800 RESPECT (that’s 1800 737 732).