Jane Wilde, speaking before the release of a film about the physicist based on her memoirs, said the couple’s eldest son, Robert, had “to do things for his father that children really shouldn’t have to do”.

She said Hawking, who became incapable of feeding or bathing himself three years after Robert was born in 1967, did not want to admit that the family needed outside help.

“Naturally he was in denial but also his mind was so deeply involved with the intellectual realms of research into the origins of the Universe that he did not have time to think about more mundane matters,” she wrote in Radio Times.

Ms Wilde said that in her “exhaustion” she had also grown to depend on Robert.

“Our gorgeous child, who was so willing to help, was having to do things for his father that children really shouldn’t have to do,” she said.

She had decided to write her memoir, Travelling to Infinity, to ensure she would not be written “out of the script”, she said, adding the couple’s marriage had crumbled after he achieved widespread acclaim. She said that when his seminal work A Brief History of Time was published in 1988, bringing fame and fortune, their lives became “very complicated”.

“I rather felt that the family had been left behind,” she said. “To me, Stephen was my husband and the father of my children; one does not say to one’s husband, ‘Oh, you’re so clever! I must worship the ground under your feet’, or in this case, wheels.

“I found this kind of sycophantic attitude — the attitude adopted by so many people around Stephen — exceptionally frustrating and, of course, it grew a lot worse when we finally had to engage carers.”

She described the difficulties of living with a groundbreaking scientist who immersed himself in work as a means of dealing with his illness. “The goddess Physics was Stephen’s idol. Sometimes Stephen would spend a whole weekend in his wheelchair, elbow resting on his knee like Rodin’s Thinker. He wouldn’t take any notice of the children, or of me, and I would become very worried,” she said. “Then, on the Monday morning, he would look up and smile and say, ‘I’ve solved that equation!’”

The couple, who also had a daughter, Lucy, born in 1970, and another son, Timothy, born in 1979, separated in 1990. Hawking then married, and subsequently divorced, one of his carers, Elaine Mason. Wilde, 70, married Jonathan Hellyer Jones, a choirmaster she had begun to lean on as her husband’s motor neurone disease got progressively worse.

She said that the film, The Theory of Everything, starring Eddie Redmayne as the physicist and Felicity Jones as Ms Wilde was “extraordinary”. It has been widely tipped for Oscar success.

Ms Wilde said she was now back in touch with Hawking. The couple appeared on the red carpet when the film had its premiere in London earlier this month.

“After Stephen’s second divorce, it became possible for us to communicate again,” she said.

“He lives 10 minutes away from us and I call in on him every so often to discuss family matters.”