Keeping secrets

[gamblore99]

A good friend tells you a secret about two other friends, about one cheating on the other. The one being cheated on is also a really good friend and totally clueless.You are not supposed to know any of this. You don't know the cheater. Would you tell your good friend who is being cheated on? If they were in a serious relatinship, getting married or engaged would that make a difference?

edited: to make slightly less confusing