“Nobody’s sexual lives are without fear, doubt, caution …” says Irish author Andrew Meehan. His fictionalised account of the relationship between Oscar and Constance Wilde in The Mystery of Love (Head of Zeus, €26.59) is so powerfully authentic, it feels like biography. Meehan, a screenwriter and academic whose early childhood was spent in Sandycove, Co Dublin and who is now based at the University of Strathclyde, Glasgow, has brought the strengths of both these disciplines to this piece of work: the scenes of the couple’s domestic life are vivid and intimate, yet the basis for them speculative.

“It’s hypothesis,” says Meehan of his account of Constance’s intimate, interior world with Oscar’s contributions presented as footnotes. “There are limits to research, there comes a point when you have done enough, you have read all the biographies, then you must raise the questions that you then answer. I discerned that there was a real relationship, they were smitten, yes, there was denial but how much denial at any given time is open to speculation, and they remained fond until the end.”

The book suggests that in the early days of their courtship and their marriage, Constance had an intelligent awareness of Oscar’s sexuality, but perhaps not of the full extent or of what might manifest as a result – the couple’s cohabitation with the young Robbie Ross, Oscar’s male lover, the scandalous repercussions. Her motivation in pursuing the relationship was complex, in part down to her desire to escape a loveless upbringing at the hands of a cruel mother and distant grandfather. Meehan translates a letter that exists from Constance’s brother, Ortho into a scene in the book where Ortho intervenes to warn her off the marriage. It doesn’t deter her. Meehan’s theory is that Oscar showed her great kindness and love, describing him as “solicitous, warm, beguiling, diffident in private”. In public, he was at the height of his early fame when they met, flush with the success of his lecture tours of America. “He was a forcefield,” says Meehan, “a charge she could plug into.”

It’s a convention to describe marriages as “doomed to fail” or “the perfect marriage”. Meehan says in reality, they just come to an end or they last. When Meehan discovered Oscar’s phrase “the mystery of love” (in Salome), he realised in choosing this as the title for the book, it would “allow me not to come to any conclusions”. It gave licence to suggest that, from the outside looking in at others’ domestic intimacies, there was no getting to the bottom of such a relationship, or indeed any relationship. Meehan believes that “marriages don’t fail, the arrangements just fail”.

Meehan’s imagining of the quotidian aspects of Constance’s and Oscar’s marriage, known for its uncertainty and torment, is riveting and entertaining. “It’s curiosity that gets you to your desk every day,” says Meehan of the process of writing it. When finishing the book in late 2018, his own mother was dying, his goodbye to her unintentionally echoing Constance’s goodbye to Oscar, when the latter was at his lowest ebb, mentally and physically, their love deep and merciful to the end.