DEAR ABBY: I have been with my wife for 23 years, married 19 of them. We have two grown children, ages 22 and 20. I recently realized she’s still in love with the guy she dated just before me. How did I find out? Well, one day my wife and I were watching a TV show together, and out of nowhere, she asked me my opinion on open marriages.

I gave her a vague answer and started investigating why she asked me that question. That’s when I discovered text messages, phone calls and her diary for the last nine months. As far as I can tell, they haven’t had sex yet, but she wants to. I did not confront her about it. I felt bad for invading her privacy, but then again, she was being sneaky. I need to know if I should stay or go. — UNCOVERED IN PENNSYLVANIA

DEAR UNCOVERED: Copy those texts and her diary. Then have a talk with your wife and ask her why she asked about your feelings on open marriage, because it was out of character. After she answers, say you have been thinking about her question and STRONGLY feel your marriage should be monogamous. THEN tell her you have seen the calls, texts and diary, and if she wants to have sex with her old boyfriend, you will file for divorce.

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Dear Abby is written by Abigail Van Buren, also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Contact Dear Abby at www.DearAbby.com or P.O. Box 69440, Los Angeles, CA 90069.