In the language of online message boards devoted to infidelity, BS is the betrayed spouse. EMA stands for extramarital affair. There are PAs and EAs—physical affairs and emotional affairs, either of which may be precipitated by an MLC: midlife crisis. D-Day is discovery day—the day you find out about an affair. OM is the other man; OW, the other woman; OMW, the other man's wife. AP is affair partner. WH is wandering husband. The WS (wayward spouse) is said to be in the "affair fog"—so consumed and distracted by the affair that he or she becomes irrational. They can't even trust themselves.

The forums, which are dominated by women (with the occasional DH, or dear husband, weighing in), are part support group, part reality check. As in any social community, friendships are made, advice offered and taken, even though the "posters" know each other only by their chat-room handles. Veteran posters are armchair psychologists who have co-opted the language of addiction: Adulterers trying to repair their marriages are "in recovery" and worry about "triggers" that may resurrect their spouse's rage.

Each site has its own attitude. has feature pages devoted to outing the betrayers. Users can post a picture of a cheating man (a sort of America's most wanted for two-timers), and the most popular message board is called Catch a Cheater. The claws come out. In one thread, scorned wives name the other woman who they claimed cheated with or stole their husbands, complete with their cities, states, and physical descriptions, none of them flattering. When one wife dubbed the OW a "manhole my ex-husband kept falling into," posters gleefully adopted the term.

At the other end of the civility spectrum, calls itself "your safe place to come and share your pain and feeling of isolation upon discovery of betrayal." Wayward spouses are welcome to post, "provided they are remorseful and committed to healing." Its forums have less venom, but the pain of betrayal, and its effect on an entire family, comes through loud and clear. One distraught wife stated her anguish with a candid eloquence:

"I am really having trouble moving past this. Specifically, not being down and crying about this anymore. D-day was two weeks ago, and now we are back into the regular routine of him going to work, kids going to school, and my life as a stay-at-home mom."

"However, I keep getting hit with the stomach punch of despair at odd times. So I still cry, or just need to get in my bed for a little while. I feel really bad that my kids are seeing me this way. They don't know why I'm sad, think I'm sick, and try to comfort me. I am trying to hold it together for them."

"Each night after the kids go to bed, my WH and I have time together to just sit and watch TV. And of course, that's when my questions start. And his lack of answers. Every night."

Usually sincerity is met with well-meaning advice: On, the question "When do you know it's time to separate/divorce?" got 45 quick replies, ranging from "Have you tried counseling?" to "Do you give oral? ... It really helps smooth out the rough edges." But there are always a few Judgy Judgertons whose idea of nuance is "Kick him to the curb!"