Many of them are middle-class, many have young children.
It may sound like an unpleasant niche website for a handful of amoral people to whom wedding vows never meant very much.
But it claims to have more than 100,000 members in the UK.
But if I'm going to find out what really makes these women tick, I need to leave the safety of the virtual world and see them for myself. I arrange to meet a 41-year-old mother of two who misses "romance and flirting", in a cafe in two days' time.
She has declined to tell me her name, so I have to think of her as her web sobriquet.
Postings such as: "I want a man who can look after me and knows how to treat a woman. I'm surprised and unsettled by the forward tone of some of the material. Determined to avoid the connotations, I reply: "The Beatles." I never hear from her again.
One woman sends me a message heavily laden with sexual innuendo and I come to regard her as the mistress of the single entendre. Another woman's first contact with me included a plan for a day out together, including visits to art galleries, a stroll round a park and then "a few hours under the duvet". I'm later propositioned by someone who tells me she has an hourglass figure.
After a quick search, I get the measure of the women on the site.
"My preference is for a man who is much younger than me with rugged features," says one. This is a way of paying someone a compliment without typing out the words. And over the course of a week I get almost 100 replies, messages and propositions.
So I paid £119 for a month's membership, giving me an entre to thousands of faithless females.