My friend, we’ll call her H, has been with this guy for about 2 years now. H is friends with all of the same people that I am (we’re in a friend group together is a good way to put it). Her boyfriend is also in this friend group, mainly because he’s with her. A few days ago, my other friend (we’ll call her B), told me that H’s boyfriend was hanging out with all of our mutual friend (call her C), and ended up cheating on H with C. Apparently C called B crying and told her not to tell anyone what happened, and C does NOT plan on telling H that she got with her boyfriend. Even though they have been friends for years. B is my best friend and she told me about this despite promising C that she wouldn’t tell anyone. B has told me not to tell anyone. If I tell H what her boyfriend did with C, it will ruin my friendship with B. It will also ruin the friendship between B and C, since B promised not to tell anyone. However, if I was in H’s shoes, I would want someone to tell me. Hopefully this makes sense. Basically my friend’s boyfriend cheated on her with one of her friends. And now no one is going to tell her. I feel guilty about not saying anything, but I also made a promise and don’t want to get myself involved in the drama. What should I do?