Do you know of any instances where the "other man" or "other woman" contacted the spouse or significant other and told them their spouse has been unfaithful/dishonest?

I know of no such cases on a first hand basis, though I can envision it happening.

I have seen plenty of movies with this plot-line.

There have been a couple times, where women have called me, and asked if I slept with so-and-so. I said yes. They deserved to know.
I was was the on- and- off “other woman” of one guy for almost 10 years. That guy went threw many girlfriends, and cheated on all of them with me. When I met this guy, he said he was single, and I lost my virginity to him (I was 13). I didn’t know he was a relationship until he was kissing his girlfriend at our high school months later (10 years ago). Him and I had on and off for a couple years until I got a serious boyfriend. Years later, when I was in a serious relationship, some chick called me, and asked if he boyfriend ever cheated on her with me. I said yes.
The other time, was about 3–4 years ago. I was dating a guy, and had no idea he had a fiancé! One day, I walk into his room, and there was an open suitcase with womens close pouring out of it. I stormed out. Later I got a call for a woman asking if I had slept with this guy. I said yes, and I felt terrible.

I thought it important enough once that i told a woman that the “single” man she was dating was actually married with a child. Not because I wanted him, but if he/she will lie to the current spouse/gf/bf they’ll lie to the next one.

Yes

This might be off topic but if you found out a guy you had a fling was lying about being “separated” would you think it is the right thing to go tell her? What if they have children and you don’t want to bust up a family?
I wrestled with that myself, I decided not to tell but not sure that was the right thing.

@escapedone7 the couple in the second part of my story, had 2 young kids together. I still told the woman the truth. The guy was a lying and cheating. They ended up getting married anyway.

My mom got the call from my dad’s mistress. The thing is, this woman was just using my dad for his money. He paid for her $1000 a month condo that her “bother” lived in with her for years. Once my father couldn’t pay it any longer, she called my mom.

@jonsblond I know of a guy who was similarly extorted. When she threatened to tell his wife, he just outed her to everyone at the office and took the lumps. A wise move. Even though he was cheating, people felt sorry for him and avoided her like the plague.

My husband’s cousin cheated on his wife with the wife’s good friend. When he broke it off, the friend was very angry and emailed the wife. The wife did not believe it.

In a kind of sort of way. Co workers pulled county marriage records on a man I was seeing who’d been telling me he was in the last 6mos. of finalizing his divorce when the truth was he hadn’t even filed the paperwork until after a then recent “date”.

I dated a guy for a short while. One day, his other girlfriend (that I didn’t know about) called me because she found my number in his wallet. The big deal was not that he was sleeping with other people, because we didn’t have any kind of commitment going. She was just calling to say that I should have certain tests done at the doctor’s office (and to gripe about what a skanky horndog he was).

I am very, very glad I heeded her advice. It wasn’t too serious, but it was the sort of thing you want to catch before it got worse, and before you have a chance to spread it to anyone else. I was young and stupid. It’s one of those growth experiences.

I had a coworker, let’s call him Rudy (who later became The Worst Boss In The World), who was disgusted with our boss (let’s call him Tony), who was married, and his affair with a married woman (let’s call her Maggie).
Rudy called Maggie’s husband, and left him an anonymous message that Tony was banging Maggie. Maggie’s husband called Tony’s wife, and told her to control her husband.
The result was that both marriages were destroyed, and Tony and Maggie married, and are now happy together.
Rudy, however, ended up having an affair himself, and soon lapsed into the heinous person he now is.

Not long after I met the man I am engaged to, his wife drove to my house and introduced herself to my husband. At this point we were having a solely emotional affair, nothing physical. It was a summer afternoon and my then-husband and kids were playing in the front yard. My oldest son came in the house and told me someone had pulled up and asked to speak to his dad. At first I didn’t think much of it, then I realized who it must be and walked out. He was leaning into the car and she was handing him copies of emails she had printed out. Good times…

@spinner : huh?

@spinner Crikey!