If Friend A went and told you something that concerned Friend B, and it was something Friend B wanted to know for a while but didn't have any confirmation, would you tell Friend B?
If I tell her, he'll be mad at me, because she'll almost definitely talk to him about it, and he'll know I've told her. If I don't, she'll almost definitely find out that I already knew, and we've been such good friends lately and I don't want to ruin that.
It's not a case of ignoring it; that's the same as not telling her.
But...what if he knows I may tell her, and decided to inform me of this little piece of information in the hope that I do tell her? If that's the case, why the hell isn't he doing his own dirty work?
I know some of you may want the background story to this - they had a long relationship, but they've been apart for two, three weeks now. Friend B's been wondering whether the girl her ex is hanging out with is a new girlfriend, but her ex won't give her a straight answer and has been threatening her with all sorts (harassment orders, etc.) if she keeps contacting him. But she just wants to know. Just that one little bit of information, and then she'll leave it.
Now, he told me this morning that him and this girl are together. So now, I know something my friend would like to know. But am I going to have to tell her, or not?