I found out my wife was having an affair with a much older guy at a youth club she volunteered at. I collected evidence, such as copies of FB messages etc.
A couple times when she was inviting him over while I was out I tried to catch them in the act but each time I was either too early or late.
So in the end I confronted other man, kind of. I anonymously sent him a email ( and his boss) telling him I know, email included evidence. I told him to get lost or I would tell his wife, kids, brother and mother.
He dissapeared. I was feeling happy that the affair was over. However I subsequently found out that the guy went on to have a nervous breakdown. At around this time, the thing is I don't feel bad that I may have caused this.