What to do

So here's the thing; im in possession of some nice little information and could make two people very unhappy and most likely very pissed off at me. Fortunately for me I really don't care if they get pissed at me, well I don't care if one of them does cause he's a douche bag. Anyways the information I have is concerning a guy I know cheating on his girlfriend; iv actually come across some tangible proof that couldn't possibly be ignored. Its an MSN conversation between someone (whose name I will not mention here) and the girl the guy was cheating with where she states that she was fucking this guy and that she lied about it so he wouldn't get in trouble with his girlfriend. So I got my hands on the conversation history and now im wonder what I should do. Do I give it to the girlfriend and she will no longer deny that her boyfriend is a little douche bag? Im a bit conflicted because im kind of friends with this girl and as much as I would like to see her dump her asshole boyfriend I know that doing with will really hurt her. Plus I wouldn't want to get the person who actually had the conversation in trouble seeing is that the two (guy and his girlfriend) are his best friends. So for now I may just sit on this information and maybe if any of them piss me off enough I'll let it out.

Here is another little... hypothetical... situation to mull over. What do you do if you were at work and looked over to see your boss's wife standing in the window in only her underwear? Do you laugh and tell you boss and hope he finds it as funny as you? Or do you casually walk away and pretend it didn't happen and hope that no one witnessed the little event?

I just pre-ordered Thom York's solo album The Eraser. I all-a-glow with excitement.