Since there are not children involved, yet, tell before children DO get involved. Think of them. Good luck.

Yes! I believe you should tell her. But I agree with the other posters, don't do it at work, and if I may suggest, do it on a Friday or Saturday, so she has the weekend to process the impact.

I have actually done what you are thinking about doing. For similiar reasons. Long story short, she didn't want to know, was pissed off at me, claimed I was trying to break them up (keep in mind that he had left her 4 years prior and moved in with me. It took me a year and a half to start picking up on his narcissistic lies and the fact that he was cheating on me. The karmic irony was NOT lost on me.)

None the less, I found out that he was stringing his wife along (to keep his health insurance with her employer and to keep the house) as well as pursuing a high school flame he crossed paths with at a reunion. Not one of us knew that he was playing all three of us, until I blew the lid off of his 3 houses of lies. (Good God, I sound like a Jerry Springer episode!) I'm an mid-upper class, educated, independent woman!

Anyway, I kicked him out, compared notes with the other girlfriend (who he was lying like a rug to as well so in turn she kicked him to the curb as well) and told his wife that the slimeball was heading back in her direction. I also made a point of APOLOGIZING to her for my poor judgement, and was warning her because I had learned how she felt, and I would want to know if the situation was reversed, so that I could make an informed decision.

She took him back, and he rolled right back into a marriage he once claimed was dead and sucking the life out of him. I assume they are still together. But either way, I feel as if I armed her with knowledge (the truth hurts, but it's the only defense to lies) and I put him under a microscope to such a degree that I bet he thinks more than twice about ever cheating again.

P.S. John Edwards is exactly like the slimeball Lawyer I have introduced in telling you this experience. Women; be very,very wary of any man who is too smooth and too charming. If these narcissitic jerks can con a cynical broad like me, they can con anyone.

Just forget this idea that you are important and at the center of some drama. You are not.

Walk away. Let his marriage take its course. Next time you meet a guy you like, do yourself a favor and ask him a few questions about himself and his family before you drop you pants.

If you get HIV tested and come up positive, you would want to notify your ex and possibly his wife too, but that is an unlikely scenario, even though so many Salon posters are obsessed with the idea. Otherwise stay out of her life.

Just walk away from this guy AND his wife and leave it at that. You don't know her; she most likely knows something is up and is just as fucked up as he because she is still with him. You need to protect yourself and extricate yourself from this relationship without causing any more hurt, pain, or drama.

You need to ask yourself WHY you stayed in this relationship against your will and work through this. It would be TOTALLY different if he were just a good bang in bed and all you got out of it was sex, but that doesn't seem to be the case. I'm all for having "fuck-buddies" to relieve some stress and have a good time, but, for sure, married guys are dangerous, always because there is that ever-present danger of actually falling in love with your fuck-buddy.

She needs to know-- it's a health issue. He's not going to tell her he's trolling the internet. So it's up to you.

Oh, and you also ought to get tested for STDs. Just one more test in your new life-- start completely afresh.

reading your letter it sounds as if you expect some good ol' female bonding and commiserating over what a creep he is...well here's some news...you're also a creep and she's going to be angry (she probably already knows he's a cheater) and might have been fantasizing for a long time about punching one of her husband's sluts in the face! Do you really want to afford her that opportunity.

Send her an anonymous email with some appropriate links and limited details explaining that she might want to think twice before moving on with this guy.

And then go away and never, ever, ever, ever have contact with either of them again. And stop sleeping with married men once you find out they're married!

...the sentiment that the LW has betrayed the wife? The LW is not married to the wife, she did not make any vows to her, she is not best friends or even acquainted with her, she started dating a man thinking he was single.

Is it poor judgment not to dump a guy you've been dating for a year once you find out that he lied to you about being married? Absolutely.

But she did not betray the wife, the wife's husband did that all on his own by actively seeking out women he's not married to, regardless of whom he did or did not sleep with.

Of course, the LW needs to break up with the guy, get herself tested, and then send the wife a letter or email letting her know what's up. I would even suggest that she open a separate gmail or yahoo email account and forward all the emails she's received from the husband to it, copy and paste in all the online ads, urls, google search query results, and send the login information for the email account to the wife. The husband will have a hard refuting online, time-stamped emails with full mail headers as opposed to print-outs.

If the wife logs into the email account, she'll see the LW's email address and can contact her directly if she wants, depending on her comfort level. Meanwhile, the LW should move on.

I doubt there is anyone here who can say they never exercised poor judgment regarding a relationship. News flash, people make mistakes and poor decisions when they think they're in love which I think only proves that they're human, not evil scumbags.