Dear Abby: My sister has been having an affair with a married man. When I asked if he was going to leave his wife, she said no, and it was fine with her. She claims his wife is fat and that they have a son with severe disabilities, and she (my sister) wouldn’t want the responsibility of that, even though I’m sure the boy would stay with his mother.

She refers to him as her “honey,” and he buys her things. (She has always been materialistic.) She stays in contact with him constantly on her iPad and says how much he loves her.

I would want to be open and have everyone get to know about my honey instead of sneaking around. When I say I don’t believe he loves her, she gets mad and accuses me of being jealous. I also told her that if I loved someone, I’d want to be with him and not communicate via email. Gifts wouldn’t make up for the person not being with me, especially if I claimed to love him.

I was in a relationship with a married man once, but I wasn’t happy about it and ended it. Am I off base because I feel the way I do?

Sneaking Around in Maine

Dear Sneaking: You’re not off base. But you’re also not your sister. The two of you appear to have very different values. While you want a full relationship, the “crumbs” and goodies she’s getting from her honey may be enough for her, and she may regard their stolen moments as exciting. If she were hoping for more than the status quo, I would say she’s wasting her time. But she seems to know the score.

Dear Abby: I know three people who have cancer. One is terminal, one is probably terminal and the other is possibly terminal. The second and third individuals I’ve known for a long time. The terminal person, however, is a social acquaintance — someone I met through a close friend.

Over the last two years we have socialized a half-dozen times, but we’ve never had an extended conversation, and I don’t especially like her. As her condition has worsened, she has withdrawn from most socializing. I receive updates from my friend, who takes her to appointments, shopping, etc. when she can’t drive herself or when she feels the woman needs company. Officially, I don’t know anything. But I was told her oncologist has informed her she’s got six months.

My question is: Should I contact her? I’ll feel like an idiot and like I’m invading her privacy if I do, yet somehow guilty if I don’t. The only thing I would say to her is that I’m sorry this has happened to her. My gut tells me I should keep quiet, but my guilt is getting in the way.

A Friend of a Friend in New York

Dear Friend: I assume you know as much about this woman as you do because your good friend is confiding in you. If you don’t know anything “officially,” I assume your friend was sworn to secrecy and chose to tell you because she receives emotional support from you. I see nothing to be gained by inserting yourself at this point, and you should not feel guilty for keeping your distance. Listen to your gut.

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.