[cufan86]

You catch a friend of yours fucking your best friend’s wife. No plausible deniability. No question what you saw.
They saw you so no anonymity.

Would you tell or best friend or keep your mouth shut?

My answer: crappy situation. But my best friend is the closest thing I have to a brother. I have his back always. I tell him. What he does at that point is up to him. If he wants it to remain a secret, no one else ever learns from me. But it would kill me to keep that from him.