if someone was doing the dirty on their wife...

Person_one

I would always tell somebody, even taking the risk of them being angry at me. I'd feel so humiliated if I was the last person to find out about my OH's infidelity, it would be insult on top of injury.

A marriage/committed relationship is essentially a contract and I think the injured party needs to know if the other is breaking the terms.

bryanb

I did this some years back. The wife did not believe me (she didn't want too so she didn't)

Primrose

If the wife was a very close or dear friend of mine, I'd be tempted to to tell the guy that I was giving him two weeks to drop the affair, confess to his wife or sort things out; otherwise I'd be letting her know.
If the wife was only an acquaintance, I think I'd still drop him a hint that people were talking about it and he'd be wise to get his act together.

missindecisive

ive been in this situation....I knew my brother in law was cheating on my sis-in law...for years.
never said a word. I figured....
she probably already knew, he was going out regularly and staying out till all hours.
they had 3 kids..I did'nt want to be the one who stirred trouble,I had no concrete evidence. it would cause mayhem and the kids would suffer.

in the end about 7 yrs later, he got caught out and finally left her.
she was shocked but kind of admitted that she knew things were'nt right between them all along. she had been choosing to ignore the situation because it suited her for various reasons, she was'nt ready to face the end of her marriage.

im glad i kept quiet. things ended in due course and thats whats happened. I didnt get involved,so therefore had no arguements/guilt/whatever placed upon me. I still can see both parties. ignorance is bliss