From Guardian:
Ted Hughes’s wife, Sylvia Plath, famously killed herself. But what of his mistress, who four years later did the same? For the first time, Yehuda Koren and Eilat Negev tell the story of the woman that the poet tried to hide. In May 1962, Assia and her third husband, the Canadian poet David Wevill, were invited to spend a weekend with Plath and Hughes, who were then living in the village of North Tawton in Devon. It was on that weekend, as Hughes later wrote in a poem, that “The dreamer in me fell in love with her”. Six weeks passed before he and Wevill met alone for the first time, when he came to London for a meeting at the BBC.
But Plath was quick to discover the budding affair. She ordered him out, and he was happy to comply. The following day he knocked on the Wevill’s door carrying four bottles of champagne. Wevill made no secret of Hughes’ ferocious lovemaking among her office friends. Equally repelled and fascinated, she told Edward Lucie-Smith, “You know, in bed he smells like a butcher.” In the next two months he shuttled between the two women.
In mid-September he and Plath took a holiday in Ireland. On the fourth day he disappeared. His whereabouts have remained a mystery not only to Plath but to subsequent biographers and scholars. However, in our research we discovered that when Hughes embarked on the Irish trip, he already had a ticket to another destination. Ditching Plath in Ireland, he hurried to London to meet Wevill, and the two of them headed south for a 10-day fiesta in Spain. He and Plath had spent their honeymoon there, and she hated the country. For him and Wevill, the trip was a delight, providing them with a creative boost: a film script that they had started writing together.
When he returned home, Hughes had a terrible row with Plath; he refused to give up his mistress and left for London permanently. Two months later, Plath moved to London as well. Hughes and Wevill were no longer making a secret of their affair. They were seen everywhere, so much so that many people mistakenly thought that they were actually living together.
On February 11 1963, Plath ended her life. Two days later, Myers came for a condolence visit and found Wevill resting in Plath’s bed. A month later Hughes and Wevill decided to abort the child that Wevill was carrying.
More here.