Okay, I have a situation going on here that I'd like to hear some viewpoints on. The group of friends with whom, until very recently, I spent most of my time included my best friend, B, whom I've mentioned before (the one with Asperger's); D, who claims to be a Christian, and has the unspoken belief that he is both smarter and more moral than everyone (he actually manages to be pleasant company on occasion, though); E, who is a sixteen-year-old girl and bipolar; L, who is a nineteen-year-old boy; and J, who was L's lover until very recently. Okay, so E has emotional problems related to the bipolar thing and a seriously dysfunctional family. Like many girls who have no relationship with their biological fathers and no strong father figure to replace him, she has a tendency to enter into unhealthy sexual relationships in an attempt to get male attention. When D brought E into our group a few months ago, she immediately started cuddling up to every guy there, and I mean that literally. Because we were all sympathetic to her emotional problems, we tried to be nice about it, especially we girls, who found her behavior particularly annoying and offensive. Everyone except for L tried to talk to her about how what she was doing was self-destructive, how she was inviting predatory older men to take advantage of her (as has happened twice since I've known her), how it was rude and inappropriate for her to come on to men who were taken, particularly when they were taken by women who were her friends, etc. Day before yesterday, we found out that we had been wasting our breath. She called my friend, B, and told him that she had had sex with L, J's boyfriend, and that she had broken it off with him in a fit of guilt and remorse, and that now he was sending her crazy text messages, all upset and threatening people. Needless to say, J knew nothing about any of this. B told me, and we told her, and the shit completely hit the fan. Obviously, no one is the slightest bit inclined to forgive L, and he will be reported to the authorities for statutory rape. J is a decent girl, and though very hurt, would have forgiven E eventually for one transgression, but it turned out that they've been screwing for the last five weeks, all the while continuing to be guests in J's house, pretending nothing was wrong. So she's asked, very reasonably I think, to not be required to ever see E again, and B and I intend to comply. I don't know what D intends to do, but we plan on making him respect her wishes on this. Here's the ethical question (sorry this was so long): it turns out that D knew L and E were cheating behind J's back all this time, and didn't tell her, or anyone else. He simply pretended everything was fine, and let her continue her relationship with a lying, cheating snake in the grass and continue offering hospitality and kindness to the girl who had chosen to view her life as a shopping mall for bed partners. D feels completely justified and in the right in this, because he says, "It wasn't my secret to tell." J feels that this is a completely retarded position to take (B and I both agree with her). As she said, "If they had decided to steal my jewelry and hock it, would he have covered it up because THAT wasn't his secret to tell?" I feel that loyalty to friends is all fine and dandy, but when loyalty to one friend requires you to do or allow harm to another friend, you have to go with the one who's an innocent party. This isn't just a matter of betrayal of trust, either: E is bipolar, and has been molested at least once that we know of in the last month by a friend of a guy she knew; she cuts herself, as I'm told a lot of bipolar people do; in short, she's a health risk. By having sex with her without telling J, L risked picking up and passing on any number of blood-borne diseases, not least of which are HIV, syphilis, and hepatitis. And D aided, abetted, and facilitated any potential health risks to J by keeping quiet. What do you guys think? Is it ethical to keep your mouth shut when one of your friends is betraying another friend? Or do you owe it to the friend who's betrayed to tell her what's happening?