A new account of the famously open affair between French literary giants Jean-Paul Sartre and Simone de Beauvoir sheds fresh light on how the relationship left regret, anger and heartbreak in its wake.

Hazel Rowley's Tete-a-Tete, which details at least 14 affairs the couple had outside their own, is being issued in two versions after Sartre's adopted daughter and keeper of his legacy raised objections to the use of unpublished letters.

"Ever since they died, much material has come out so we've been hit with thick volumes of their letters," Rowley said from her home in New York. "But nobody knew anything about these characters who surrounded them.

"Part of my job was to build and portray in technicolour the characters who formed what Sartre and Beauvoir called 'the family'. You can't understand the relationship between Beauvoir and Sartre without understanding the other intimates."

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