Infidelity, sexual intrigue, lying, cheating-these are the forbidden words of marriage. But is it still realistic to expect wives to remain faithful to their husbands? Kate Morris is an English writer who turned the age-old assumption that men stray while women stay put on its head in her novel, The Seven Year Itch , which this summer became one of the U.K.'s hottest beach reads. The book is currently waiting for U.S. publishers to fight for the right to bring it out here, but meanwhile, you can buy it here . Below, Kate explains why her own life experience prompted her to explore this touchy subject in fiction.

It was about six months after my seventh wedding anniversary when I became aware that I was finding random men attractive. I was interested in nearly every man I met, including my son’s gay headmaster. Before marriage I had been very discerning, but after seven years of marriage, it was a different story.

What was going on? Perhaps it was because my children were out of nappies and I no longer felt like a joint proprietor of a small, noisy nursery school. Perhaps I was worried about growing older and wanted to be admired. Conversations with my husband had become predictable. We no longer talked about art or literature or film; we talked timetables and children. One lunchtime, I realized with shock that we were both scheduling operations, him something to do with his knee, and me a hernia. It was all so mundane, unsexy, and middle-aged. To make sense of it all, I began to write a fictional column for Tatler magazine in England. The woman I invented had been married seven years and inevitably looked outside her marriage for love, something I didn’t dare do.

My agent suggested and sold the idea for my novel, The Seven Year Itch . I began to think more about the subject from a woman’s point of view. Why is that men have traditionally been the ones to stray from their marriages? Is it because when a couple divorces, the average income of the woman often plummets by 20 percent or more, while the man’s stays the same or in some cases rises? The assumption is that after women start a family, they want stability for the sake of their children. Women may daydream about having affairs, but they don’t actually go searching for men. They don’t want to deceive their families. And when would they find the time or the energy to skulk around bars? Is it simply that their sex drive isn’t as strong as a man’s? I wanted to write about what happens when a woman does follow her heart. What are the consequences?
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I have a friend who has recently taken a lover. She is not married but is in a long-term relationship, and has four children and a stressful freelance job. She says her relationship is stale and she is enjoying the attention that the new man gives her. Her partner doesn’t know yet. I have another friend who has been married for about 15 years and has not had sex for two. She describes her husband as white, flabby, and sweaty, and does not want to have sex with him, although she loves him and feels lucky to be married to him, as they get on very well. He has rejected her sexually, and she has learned to live within a sexless marriage and no longer even wants to have sex with him. But the other day, she confessed that she had asked a single girlfriend to find her a lover.

There is no doubt in my mind that women enjoy the thrill of the chase, the intrigue, and the passion of a new affair, just like men, but are more concerned with saving the sanctity of their marriages and keeping it together for the children. It’s unlikely that they are going to seek out extramarital sex, or meet someone on an airplane and take off, leaving their children behind. A married girlfriend of mine lost her husband to a woman he met on an airplane. He’s a documentary maker and travels all the time. He has left three children and a devastated wife and even moved countries to be with his new girlfriend.

Ellie, the character in my book, takes a lover, but only for one weekend, and she knows it's wrong but feels justified. Her husband, Jack, is an actor, who has been made redundant from a daytime soap, and he’s now under her feet and suffocating her with his demands. At the time I was writing the book, I didn’t have any female friends who had conducted affairs, but I could imagine Ellie’s frustration. She has been a stay-at-home mother for a year or two. The last straw is when she goes into Gap and hears herself saying, "It’s a shame you don’t do those shirts with the teddy logos any more." But Jack does not support her idea to start a business, even though they now need the money. The book is a chastening tale and had a surprising ending that some people were disappointed by and others loved.

Maybe if all marriages could get back on track, after infidelity, perhaps the odd liaison would enliven a stale marriage. I don’t have the answers though. I just don’t know.

Kate Morris lives in London with two children, Jude, 8, and Belle, 5, and her husband, Luke, a photographer. She has published two novels and is currently just starting work on a third. She blogs at Easy Living Magazine .