There are two people in a relationship; let’s call them Kristi and Peter. I’m really good friends with both. One weekend night, Peter used my laptop to play a bunch of new songs he found. As a college student obsessed with social networking, he checked his Facebook account while using my laptop. The next morning I noticed that he had neglected to log out of his account. At that moment, a girl messaged him, saying “I love you babe! So excited for you to visit me next week.”
This girl was not Kristi. I clicked her account and saw that this mystery girl goes to Penn State University and that their messaging stretched back over a year. Peter is obviously involved in a relationship with this girl, while also dating Kristi. My dilemma is whether to tell Kristi about this. Telling her would damage my friendship with Peter and reveal that I read his personal messages. Not telling her would damage my friendship with Kristi and allow her to stay in a relationship with someone who is cheating on her.
Contributed by Anonymous.
To comment on this dilemma, leave a response. For anonymity, omit your email address and website, and use a screen name.
Ethical Decisions 
[Edited for grammar and clarity.]
You have two choices: tell Kristi that Peter is cheating on her, or don’t tell her. In one case you damage your friendship with Peter, and the other case with Kristi. So if your choice damages a friendship, it is not your fault, but destiny.
Telling Kristi that Peter is cheating on her is not unethical, because if this damages your friendship, the true cause of the damage is Peter’s behavior. On the other hand, if you don’t tell Kristi, then any resulting damage to your friendship with her is avoidable. You are the cause, not her. The ethical choice is therefore to tell her.
Both choices appear to be generalizable. If we suppose that the reason for telling Kristi is to preserve your relationship with her, then this purpose could be achieved if people always revealed love triangles of which they are aware. If the purpose of not telling her is to preserve your relationship with Peter, then again, this could still be achieved if people never revealed love triangles.
Therefore, the ethical decision is to tell Kristi about Peter.
LikeLike
I’m not sure “cheating” is the right word for Peter’s behavior. This word is usually reserved for infidelity in marriage or some other strongly committed relationship. What we have here seems to be more like a romantic or sexual liaison. This is an important distinction, because in most cultures, marriage entails an implicit (or explicit) promise to be faithful, while this is not so clear for a premarital affair.
I agree with Yihua that either of the available choices seems to be generalizable.
Both you and Yihua focus primarily on virtue ethics, specifically friendship obligations. I agree that friendship is an important element in this case. I am puzzled, however, about why failing to reveal Peter’s affair to Kristi would damage your friendship with Kristi. Neither Kristi nor anyone else need ever know that you were aware of the relationship.
In any case, friendship obligations are not about avoiding damage to friendship. They are about caring for one’s friends, which could even require breaking off a friendship. In this case, your friendship obligations unfortunately seem to conflict with each other, which makes it hard to obtain guidance from virtue ethics.
That leaves the utilitarian principle, which speaks rather clearly in this case. Meddling in personal affairs always carries a large downside risk, due to the volatile and unpredictable nature of intimate relationships. It can be utilitarian only there is a substantial and clearly identifiable benefit. It is hard to imagine how telling Kristi about Peter’s fling can improve matters, even a little.
The best course is to say nothing about the personal correspondence you read — unless you are specifically asked about what you know, which would raise another ethical issue.
LikeLike