When I interviewed Paul Theroux 21 years ago at his home in Hawaii, there were already rumours that his ex-wife Anne had written a book about him. In fact their son Marcel said in an interview that she had sent Paul the manuscript. Theroux denied it to me, and said breezily that he wished Anne would write a book, because then she’d have greater respect for the work involved. And:

I don’t see that if she wrote a book it’s going to be an attack on me. I don’t think it’ll be ‘I discovered his lies’. So it doesn’t worry me. I’m sure she’d show it to me, but it doesn’t really matter — I’m happy to just buy it off the bookstalls.

So is this the long-awaited book? Has it been sitting in a drawer gathering dust over the years? If so, why publish it now, when Paul Theroux is probably better known as the father of Louis than as the great novelist and travel writer he once was? Anne only explains in a postscript that she wrote the book soon after Paul left her, but by then was working as a relationship counsellor and felt she could not publish it until she retired. She has now retired, so here it is.

Is it worth the long wait? Not really. It is based on a diary she kept in 1990, the year Paul left her. They had married in Kampala in 1967, when they were both teaching there. She was already pregnant with Marcel, and Louis quickly followed. They moved to Singapore for three years, before settling in England. But Paul never really settled anywhere for long. He went off to teach in Virginia for a term and then embarked on the first of the long travels that would make his name and fortune in The Great Railway Bazaar. He bought a house in Cape Cod and invited Anne and the boys to join him for their summer holidays, but he also often stayed there alone.

Anne suspected that he was having affairs, but consoled herself with the thought that he always came back to her, which he did. But when she had an affair in 1973, and he found a note her lover had sent her, he went berserk. It inspired one of his finest and funniest chapters — the scene in My Secret Historywhere he breaks into a dinner party and shoots his love rival with a urine-charged water pistol. This didn’t actually happen; but he did reproduce Anne’s lover’s note word for word, and she was naturally upset.

When, in January 1990, Paul said he was going away for six months, Anne started the diary. But it is more about her quotidian activities than about her husband. She is living alone in Wandsworth — both sons are at university, Marcel at Yale, Louis at Oxford. She works as a radio arts producer and goes to interview Barbara Cartland, Kingsley Amis and V.S. Naipaul; she takes little holidays in Budapest, Crete and the Lake District; she attends an Insight course and a personal development seminar; she applies for a VSO placement, but doesn’t get it.

These are the highlights. More typical entries are: ‘Saturday 4 August. The Metcalfs came. Cooked chicken’; or ‘Saturday 6 October. Bought floor tiles’. There is a little cliff-hanger on 10 June when ‘The Worgans [her sister and brother-in-law] came for lunch. David annoyed me by criticising the front door lock.’ She promises she will expand later and does — her brother-in-law jiggled the ill-fitting lock and told her: ‘Fucking cowboys really took you for a ride.’ At which she explodes: ‘Well, what the fuck am I supposed to do?’ This is more like it: for a minute we get a glimpse of raw emotion. But that is unusual.

As the year draws on, it becomes increasingly apparent that Paul is not coming back. He has fallen in love with another woman and is already living with her. Anne is an abandoned wife who, like so many abandoned wives, decides to train as a relationship counsellor. I hope she found that her true metier.

The mystery is, how could someone who was married to Paul Theroux for 22 years, who read his books and knew how hard he worked on them, be so completely oblivious to the art of writing? She surely should have noticed that it is not just a matter of recording ‘Bought floor tiles’.I expected — in truth, hoped — that this book would be a bitter attack that would trigger a brilliant riposte from Theroux, like Sir Vidia’s Shadow. But it isn’t; it is just a sad book by a sad ex-wife who sadly can’t write.