Vow: A Memoir of Marriage (And Other Affairs) by Wendy Plump: review Wendy Plump had been married for 18 years when she found out about the Other Woman. Susan lived, apparently, a mile down the road in a house that Plump's husband, Bill, had bought for her; and living there also was their eight-month-old baby boy. "The news fell into place," Plump writes, "with an almost audible click. Like a bullet revolving in its cylinder and lining up with the chamber. Plump uses this image because it describes the "kind of violence that I lived with later on," but the marriage between Wendy and Bill had been a crime scene from the start. Vow is not the kind of memoir usually written by a bruised wife bent on revenge, but then Plump was not the usual kind of wife, and it is not revenge that she is after. For a start, she had affairs of her own (three in all: honesty is what Plump does best), all of them in the early years. By the time Bill met Susan, the Plumps had a "360-degree view of infidelity. We knew it from every angle. Wendy was unfaithful because she was young and excited and wanted something inexpressible. She just wanted, and wanting, she says, puts a terrible strain on marriage vows. What Plump didn't want was for her marriage to end; she loved her husband and she liked their life. But she was hungry, and as W H Auden reminds us in the epigraph to the book, "Hunger allows no choice." Plump, who has a healthy appetite, sexual and otherwise, likes her men raw rather than cooked. Her idea of a good date varies from shark-fishing to riding on a snow mobile. She drank vodka in snooker halls with her first lover, trekked through forests with the second, and fell for the third because he "smacked of hearth and gun, taxidermy and buckshot. It felt like coming home. The walls of her parents" house in Pennsylvania are festooned with animal heads, and a stuffed grizzly bear shot by her father sits with them in the living room. With more testosterone than the average trucker and the energy of a teenage boy (she has two of these, as well), Plump is tough and brave and plays fair; Bill was apparently none of these things. The "noble, utterly cool young man" she fell for in college died and was replaced by the shadow we meet in these pages. Plump, who approaches the effects of infidelity like a hunter stalking the target, recognises the part she played in breaking her husband's spirit. Like all books which take an aim at the truth, Vow may change the way you see yourself; it will at least change your marriage. This is not because it is a morality tale or an account of infidelity that will scare you enough not to give it a go. It would be easy to produce this kind of book, and Plump doesn't take the easy way through anything. What makes Vow so powerful is that she dissects not only the carcass of her own marriage, but the drive that propels so many otherwise sane people to destroy, for the sake of a moment of wanting, the bullet-proof world they have tried to create. Plump, who is now as wise as a serpent and as harmless as a dove, suggests that monogamous couples - at whom she gawps as though they were animals in a zoo - are committed less to their spouses than they are to themselves. Fidelity "has to do with their own honour." But Vow is not just about infidelity. It is also about animals, the real love of Plump's life, and her writing takes off like a Ted Hughes poem when she brings in the natural world. Deceived, "we claw at our faces and stand in the snow, bawling like cows." Plump wakes one winter morning to find that the orchard, rubbish bins and bird-feeder have been savaged by deer. This is how I think of Bill's betrayal now. It had been going on all those years while I slept through it unaware. Her closing image is of geese disturbed on the lake sent shrieking with annoyance into the night sky. "I did that," she says. I didn't intend to, but I did. Frances Wilson is the author of How to Survive the Titanic (Bloomsbury) Vow: A Memoir of Marriage (And Other Affairs) by Wendy Plump 272pp, Bloomsbury t £11.99 (PLUS £1.35 p & p) Buy now from Telegraph Books (RRP £12.99, ebook £8.51)