"I am married, rather begrudgingly, to a man who no longer makes me feel anything," writes Shelly in her blog, Confessions of a Wayward Wife. "Things are OK between us. Maybe that's the problem – things are fine. But it isn't exciting or even interesting any more. Our love-making is performed mostly out of habit. If he leaves the dishes expectantly in the sink, it makes me furious. Even the way he moves in bed makes me want to stab myself in the eye with a fork."

Fork-induced eye injuries notwithstanding, these admissions don't necessarily mark Shelly's marriage out as unusual. Even happily married couples might wince in recognition at those moments of irrational fury that can accompany long-term relationships. Marriages that have gone off the boil are also not a rarity – therapist Shirley P Glass states in her book Not Just Friends that one or both parties in 50 per cent of all couples will be unfaithful, and adultery remains the most common reason cited by divorcing couples. What makes Shelly distinct is the fact that she is cheating on her husband and writes candidly about it online (at confessionsofawaywardwife.blogspot.com) under a pseudonym. And she's not alone. Shelly's blog is one of a growing number of "infidelity blogs" which attract a loyal online following.

Infidelity blogging is part of a bigger confessional blogging scene. Sites like Post Secret ( postsecret.com), which publishes people's anonymous confessions in postcard form, might have started the trend as far back as 2005 but the internet is now awash with places for the guilt-ridden to unburden their virtual souls. Secret Tweet ( secrettweet.com) enables users to post anonymous confessions to Twitter, Second Chance ( secondchance online.blogspot.com) publishes people's regrets anonymously, and True Wife Confessions ( truewifeconfessions.blogspot.com) is a forum for women to post their real-life relationship confessions. One post reads: "I know this is hypocritical but since you've gained so much weight, I'm just not that attracted to you any more."

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Dawn Rouse, the founder of True Wife Confessions, admits to writing the first 20 confessions – including less shocking revelations such as "I know where your belt, glasses or wallet are. I just think it's funny to watch you run around like a crazy person looking for them" and "Sometimes you only have to make me laugh to change my mood. It is not a strategy you use enough". But now she has more than enough posts to keep the site refreshed. Rouse offers some insights into why women are so keen to write about acutely personal issues in such a public sphere. "I feel there is a definite lack of space for women to say the unsayable; the things that we as humans need to say or lose our minds," she explains. "I may say these things in a therapist's office. Others may only have access to a blog like this. You get it out. Then it dissipates, gives you the impetus to say it to your partner, or confirms that you have some different choices to make in life."

Callie, a wife and mother who blogs anonymously about her affair with a married man, agrees. "Most of my friends know my husband so I couldn't talk to them about my affair," she confides. "Blogging was a safe way to find people who could relate to my circumstances without it affecting my ordinary life." For her, infidelity blogging isn't a brazen attempt to flaunt unfaithfulness but is instead inspired by the need to know you're normal, and not alone. "The thing that has amazed me most about other bloggers is that they are all just ordinary people trying to make the most of their situations," she says. "In one way or another, their marriages no longer work but they don't want to leave because of the broader implications. Having a community of people in similar circumstances makes it less isolating."

Blogging also gave Amy, the author of My Married Life ( marriedwifeblog.blogspot.com), a much-needed emotional outlet to talk about her affairs. "The prevailing attitude towards infidelity is: 'Work it out at home,'" she says. "People wrongly assume that someone who cheats doesn't love their spouse." Amy began blogging to explore whether other people shared her view that loving her husband and having affairs were equally legitimate parts of her life, and she soon found a virtual community of supportive, like-minded bloggers.

Tuesday Malone, a married mum who writes about her affair with a married man at insidetheaffair.com, blogs for similar reasons. "Infidelity is an extremely isolating experience," she says. "Apart from the moments of intensity you share with your lover, you are unable to share the experience with anyone else in your life, including those closest to you." Tuesday's regular readers range from people having affairs to those whose partners have been unfaithful. "Others are just interested in infidelity or they like the writing," she says. "Many of us are going through the same experiences and emotions – it's like having your own personal 'cheer squad' on the sidelines." Petal, a wife and mother in her thirties who has an open marriage following her husband's discovery of her affair, admits that she also enjoys the attention bestowed on her by her readers. "I suppose some of the comments feed my ego a bit," she admits. "Having people give me feedback is a bit heady."

Blogging, like infidelity, can become an addiction in itself – and for some, infidelity blogging can become something of a demanding mistress too. Tuesday Malone admits this. "There is no doubt that discovery would ruin my life in many ways," she reflects. "But like some perverse drug I cannot seem to give it up."

Bloggers do sometimes hang up their boots, of course. Amy thinks she'll eventually lose interest in blogging because finding opportunities to write isn't easy. Tuesday Malone agrees that her blog would be brought to a swift conclusion if her husband found it, although she takes steps to avoid that, using a proxy server, only blogging when she's alone in the house and always deleting her browsing history. She claims she's equivocal whether discovery would actually be a good thing – but she hesitates and I can't decide if the implication is that it might free her to keep blogging without subterfuge, or that being exposed might in itself be good blog material.

For many anonymous bloggers the risks of being found out are outweighed by the benefits that blogging brings, despite concern that discovery could hurt loved ones. Kimberly describes the dangers in her blog, The Errant Wife ( www.yourerrantwife.blogspot.com). "We know we could be caught, but the needs are such that they are worth the risk," she writes. "In the cost/benefit analysis our destruction doesn't seem so bad when compared to our craving ... and we all think we are too smart to get caught."

Serial Mistress, a divorcee who dates married men and writes about her experiences at serialmistress.blogspot.com, sees things differently. "People are real, and very important to me," she says. "My blog would never be written to the detriment of a relationship." Of course, it's difficult to overlook the fact that somewhere there are unwitting wives whose husbands' extra-marital exploits provide much of the content for such blogs.

There's an argument that says infidelity blogs are written to the detriment of relationships. But does guilt exist in virtual reality? Opinion is divided. Ms Scarlett, a fortysomething married mum, writes about her affair with a married man at msscarlettletter.blogspot.com. She doesn't feel guilt about her affair or her blog, and argues that's common among infidelity bloggers. "Why? Not sure. Maybe we've been pushed far enough in our real lives that it just doesn't feel wrong," she muses.

In contrast, Callie feels guilty on both counts. "I have tried to be fairly respectful of my husband and to avoid writing about him. But just learning about what I have done would be devastating to our relationship," she admits. "I don't think he could ever understand why I felt the need to do it." Tuesday Malone says guilt is inevitable but describes it as a twinge rather than a full-on assault. "Guilt should pervade my life at every turn," she acknowledges. "I am betraying my husband by having the affair. I am betraying my lover by writing my blog. But somehow I have blocked the guilt and not allowed myself to feel it. The thing I feel most guilty about is not feeling guilty."

At heart, infidelity blogging appears to be an effort to give concrete reality to relationships that often have their roots in unreality; to legitimise something that society mostly denounces. An infidelity blogger might not be able to hold the hand of her lover in public but she can create an online persona around their affair and write in intimate detail about illicit hours spent together.

Still, writing online about infidelity could be seen as a harder betrayal to understand than the adultery itself. After all, while an affair can be unintentional, or at least unpremeditated, there's nothing unwitting about blogging. It's hard not to feel pangs of pity for the partners who know less about the person with whom they exchanged vows than scores of virtual strangers. But it's not always easy, either, to condemn the choices of those for whom adultery and the internet offer a release from the realities of difficult relationships.

Either way, whether they are seeking virtual absolution or just attention, the new infidelity bloggers seem to be having their cake and writing about it too.

The serial mistress by 'Karen Marley'

I blog about my experiences as a single woman, dating married men. I started blogging to help people understand that mistresses aren't all home-wreckers and unpaid hookers. I'll always be in the firing line regarding my life as a serial mistress but even if my blog came under criticism I wouldn't stop. The typical mistress has always been portrayed as a damaged woman who falls for a man she can't have, and spends the rest of her time either pining over him or trying to wreck his marriage. I'm not interested in wrecking homes or destroying lives and I make no demands of the men I date, so I have nothing to be ashamed of. I refuse to hide just because that's what society says the "scarlet woman" should do. I love being single and I enjoy the company of successful, charismatic men who have other lives to go to when they're not with me. I love living alone and I enjoy close relationships with attached men, without it becoming mundane, without having to pick up pants off the floor, and without the grief and hassle most relationships endure.

serialmistress.blogspot.com

The yummy mummy by 'Betty Walker'

I am a mother, a partner, a businesswoman, a friend and a lover. The real me never really sees the light of day until I blog. My blog allows me to share my experience with a like-minded community. I didn't realise there were so many of us out there until I started this journey. My personal feelings are usually hidden beneath a veneer. As a mum and businesswoman I'm required to be on my best behaviour but sometimes you just need an outlet to say the things you can't normally say. Mums have it hard – society still expects us to be virtuous and homely, and we don't have the equality in the home that we do in business. We lose all sense of sexuality and self. I think this is why we are seeing a rise in female bloggers. Just to say out loud what you feel is a form of therapy. I feel guilty everyday but I'm not doing anything that hasn't been done before, it's just wrapped up in a different package. I wouldn't want to hurt anyone and that's always in the back of my mind. Maybe I'll stop when my story is told.

yummymummyontheedge.blogspot.com

The unfaithful wife by 'Amy S'

I've been married for almost seven years and I have slept with quite a few other men. My husband is not aware. I looked on the web to see if there were other women in the same situation and all I found were people being shot down by the moral police. So I started my blog as an experiment; a place to order my thoughts and talk at my own pace, and to connect with others in similar circumstances and find out if they felt the same things. I love my hubby dearly; I don't think I love him any less than someone who is faithful. My blog is not a place for evangelists against cheating, although I do listen to good advice. Maybe blogging is a justification. Maybe it's a desire for community. I write about my infidelities from an emotional and physical perspective. I love my sexuality and want to connect with others like me. Besides my friends, the people who read my blog are mostly spectators and voyeurs like me. I like reading about people who love their spouses but have discreet sexual fun with others.

marriedwifeblog.blogspot.com

The secret affair by 'Tuesday Malone'

I am a thirtysomething married woman having an affair. I started blogging because I felt isolated from both my husband and my married lover. I didn't feel I could confide in a friend as I was afraid of being judged or misunderstood, so I went to an internet café in a different part of the city, started a blog and wrote my first post. The feeling of liberation was immediate. My blog is my journey through the moral and emotional minefield of infidelity, as well as its social and personal consequences. I write about my experiences of reading between text- message lines and having to explain why one's knickers are in one's handbag and not on one's person. Blogging enables me to share my experiences with a like-minded, non-judgemental community, who provide a surprising level of emotional support and analysis. It's extremely comforting to know I am not alone. I began writing for myself, but I now write with my "commenters" in mind. I find it inspiring to write "to" this community because I know I have a sympathetic and encouraging audience. Part of the attraction is also the element of danger surrounding writing an anonymous public blog.

insidetheaffair.blogspot.com

The Scarlett woman by 'Ms Scarlett'

I started blogging because I needed somewhere to get my thoughts down without fear of judgement. I also needed an outlet before I started talking about my other life to people in my real life. I write about my relationship with my lover – its ups and downs, as well as about relationships in general. I don't really consider it public. I don't write under my own name, and there's no way anyone I know would identify me as the writer even if they found the blog. It started as an outlet, somewhere to talk about my life, but it has turned into a community, a sharing of ideas with people I've never met but who I consider friends. They know exactly what I'm talking about – we've all been through a lot of the same things. As one of them said just today, "Whoever said pen-pals are a thing of the past never tried blogging". I write for myself; it's the cheapest therapy I'll ever get. I would be stunned if my family ever found my blog and connected it to me, so I don't really worry about being caught.

msscarlettletter.blogspot.com