Does size matter?

Dear Cary,

I have been on a friendly basis with my oldest sister's husband (he's 55) ... um, let's call him Mark, since they got married some 25-odd years ago. She is in her late 40s; I'm in my early 40s and blissfully married to my husband, let's call him Clark (he's 52), for 21 years.

Despite many opportunities presenting themselves over the years, I have remained happily faithful to Clark, and I am certain he has been true to me as well. I had always just assumed Mark and my sister had a similar situation.

Recently I was on a business trip in the vicinity of their home and decided to take a side trip and visit them for a couple of days. One afternoon, my sister had to work for a few hours and the kids were at school, leaving me and Mark at home to amuse ourselves. Much to my horror, he asked me to have sex with him, and said he had been in love with me for years. This was accompanied by tearful lamentation about their sex life having been virtually nonexistent for the past year. I was not even remotely interested in consummating this one-sided lustfest, and dismissed the idea in as lighthearted a manner as I could. (I asked him if he'd ever seen "Hannah and Her Sisters" -- he hadn't.) A couple hours later, everyone came home, everything was fine.

So the obvious question: Do I tell my sister? Do I tell my husband? Do I tell anybody? If I try to put myself in her position I think I would want to know. However, I'm afraid if I go to her she won't believe me, or will think he was just kidding (he wasn't), or they will get in a big ugly drama of my making. I sort of want to tell Clark, but I'm not sure what his reaction would be either. In retrospect the whole scene was just really weird, and I wish I had reacted with more shock and horror, because that's how I feel now. I am best friends with my sister and don't want to jeopardize that. We only see each other's families about once a year, but next time is gonna be weird. Thoughts? Advice? (Honestly, I feel better already just putting this in writing.)

I think I know that I just need to keep silent about this and hope nothing ever happens again ... right? Thank you!!

Dear Hit On by the Brother-in-Law,

Yes, I think you are right that the damage and the costs of telling your sister would vastly outweigh any good to be gained from it. However, do not just try to shut it away in your mind. Instead, take it as evidence that your sister is in some sort of danger, and reach out to her. Become even closer to her, because eventually something is going to go wrong in her marriage, and she will need your support.

And if you find yourself waffling, wishing to tell her, and need to see clearly why you cannot tell her, consider: It would force her into an agonizing conflict: Either her husband is untrustworthy, or her sister means her harm and is trying to wreck her marriage. That would cause her much suffering with little positive result. If there is a way to inquire discreetly if there are problems in the marriage, OK. You would know best. But, in spite of what seems right, telling her would just be like blowing up a bomb in her living room.

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