DEAR ABBY: My sister likes a childhood friend of ours and is hiding the fact that they are together, even though everyone in the family already knows they are living together. She clearly doesn’t want me to know, and always finds a way to not be truthful with me.

This guy and I were friends, but whatever my sister said to him made him cut our friendship off. I’m hurt that she needs to lie to me about their relationship, because it doesn’t matter to me. I’m happy she has found someone who makes her happy. She even has our mom covering for her. Should I say something, or just let it be? — HURTFUL AND SAD SISTER

DEAR HURTFUL: Did you and your sister’s boyfriend ever have a romantic relationship? If the answer is yes, it may explain your sister’s strange behavior and your mother’s willingness to cover for her. Because the cat is out of the bag and “everyone” knows the truth, I see no reason why you shouldn’t talk to your sister and clear the air. When you do, wish them well.

Read more Dear Abby and other advice columns.

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.