The Act of Love By Howard Jacobson Jonathan Cape 308 pages; Â£17.99 'No man has ever loved a woman and not imagined her in the arms of someone else," muses Quinn, the principal of Howard Jacobson's new novel, The Act of Love. "No husband is happy - truly, genitally happy, happy at the very heart of himself as a husband - until he has proof positive that another man..." Jacobson, the British author of 10 novels including The Mighty Walzer and Kalooki Nights, presents, through his new book, an audacious premise: that all men, according to Quinn, his narrator, secretly, even unconsciously, desire their wives to be unfaithful to them. This proposition is something of a provocation, and it is to Jacobson's credit that he is able to expound upon it credibly through the misadventures of his anti-hero. Quinn professes to be a happy man. He owns a respected antiquarian bookselling business in the center of London and is married to the elegant Marisa. That she is cheating on him does not detract from his contentment; rather, it enhances his satisfaction with his wife, and life in general. This peculiar state of mind is informed by two significant events. The first was Quinn's first flirtation with rejection, at 15. His first girlfriend - "the first girl whose fingers I was allowed to interlace with mine" - abandons him on their second date. They enter a cinema together, but somehow she conspires to leave without him, and with someone else. He stands vigil outside her house, forlorn and desperate, until she sends her sister out to dispatch him. "These things happen," the sister tells him kindly. "You'll get over it." The second concerns Marisa. Their relationship begins while she is still married to another, and when their misdeeds are revealed, the wronged husband issues a warning: "A woman who betrays one man will betray another. That is the immutable law of woman." Quinn takes these words seriously, and one anticipates a slide into despair. But an unexpected event during their honeymoon in Florida turns matters on their head. A moment of potential insecurity instead becomes one of heady, unexpected pleasure. He stops dreading the instant when another man covets his wife, and begins to eagerly anticipate it instead. Quinn, you see, actively wants his wife to betray him. But for him, the desire is not enough; he needs to engineer, to control the process. A chance encounter presents Quinn with the ideal opportunity, and soon he is at work to create the ideal mÃ©nage-Ã -trois, albeit with two unwitting participants. This small point is of little consequence to him; the man, Marius, is intellectually and sensually suited to Marisa. He is suitable, in short, and this is all that matters. As far as he is concerned, Quinn's actions and desires are perfectly reasonable, indeed logical, and he takes great pain to rationalize his position. The point, he tells himself, is that it would be against one's natural inclinations to resist the situation. "The instinct to share that which we find beautiful lies deep within our nature. It is not for ourselves, but for others to look at too." And there lies the nub. Quinn - like Jacobson's book - is refined, cerebral and up to a point convincing. The problem is that he is completely self-absorbed, so much so that he cannot recognize that his actions are not those of a gallant, but rather of a chauvinist. He does not see - or chooses not to see - that he treats Marisa as his property, as a chattel, to bequeath as he sees fit. One suspects that a therapist would have lots of fun parsing the contents of the book. Quinn's antecedents, before and beyond his first rejection, are material for rich psychodrama. For the rest of us, the book still presents as a stimulating literary entertainment, albeit one that once or twice falls a little short of the lofty targets that it sets for itself. Jacobson's narrative concentrates, understandably, on Quinn and his preoccupation, but this narrow focus is at the expense of Marius and Marisa. Through Quinn's eyes, we experience them flatly, as sometimes unconvincing individuals, not fully formed and instead mere bit players in his interior drama. Quinn doesn't realize this, of course, but the reader does, and sometimes one wishes for just a bit more nuance beyond the broad brush strokes that characterize the two. That said, what we lose from one side, we gain on the other. When Quinn, unsurprisingly, begins to lose the plot - quite literally - Jacobson depicts his descent with a discomfiting conviction. It is this loss of bearing that leads the book to its tragic, poignant climax, surprising but still not entirely unexpected. At its core, The Act of Love is about obsession. Obsession is hardly unfamiliar territory for literature - David Grossman's novella, Frenzy, being one outstanding recent example - but the familiarity of the theme does not hinder Jacobson from constructing a beguiling, intriguing and provocative book. It nudges one into contemplating the unthinkable, and does a fine job of convincing too. It is unashamedly highbrow - one does not always expect to find Herotodus and Cervantes name-checked in a book about, not to put to fine a point about it, intercourse - but it is funny, provocative and ultimately, very sad.

Affairs of the heart

Howard Jacobson's latest protagonist is a man who eagerly anticipates his wife's unfaithfulness.