Dear Prudence,
My girlfriend of eight years had an affair with a married acquaintance of ours, “Konstantin.” They both claim it never got physical but promised me and Konstantin’s wife that they’d stop seeing each other, then continued to do so behind our backs. After I broke up with her, my ex tried unsuccessfully to get Konstantin to leave his wife for her (Konstantin and his wife have two small kids).
I have avoided talking with friends about this—partly due to shame but mostly because we share many close friends. I do not want to burden mutual friends with this dirty laundry and make them feel like they have to choose which of us to invite to parties. I don’t need them to dislike Konstantin on my behalf—he has some good qualities, although for obvious reasons I resent him. Konstantin and I avoid each other socially, and I don’t think anyone has noticed, but it has gotten to the point where I feel like I am telling a lie by omission to my friends. Which course of action causes the least harm?
—Stuck