Advice like this is the reason I lived a lie for 25 years.

The people who could have told me didn't. I consider them as infidelity co-conspirators and of the same ilk as the betrayers. The idea presented here is waywardness.

I disagree, by the AP or the APs spouse not telling me allowed just enough darkened to continued the secrets and the affair after her husband found out. Had both sides of the parties been made in the light my husbands affair would have ended 5 years sooner and I would have had 5 less years stolen from me. Also my husbands APs husband tried to stay and he was successful at forgiving her, but the second time their marriage did not make it. Had light come sooner I believe their children could still have an intact family. It’s a shame they recommend you to help with the secrecy in my opinion.

It’s not always about wanting someone else to suffer, it’s about wanting them to fully know the truth of the situation. Is it really better for them to not know the true nature of the person they are married to? Really?
There is a huge weight carried by those of us that know the real truth and asking me, the betrayed to bury that information and carry that burden in my heart when I know it’s wrong is not the right thing to do. People’s lives are affected by not knowing. It’s not ok to watch them live a lie.
This need to tell them does not always come from displaced anger, it can be from a place of love and kindness for someone else.