DEAR MISS MANNERS: My brother is getting married for the second time. He first married about 25 years ago, divorcing 10 years later.

Since then, he has left a trail of destruction and heartbreak: He has cheated on, and lost, a series of partners, and even got fired from a lucrative job because he conducted multiple affairs with employees. His behavior has so alienated his children that they are now barely on speaking terms. He admits to his transgressions, but resents that his children avoid him and are not supportive of the upcoming marriage because they are appalled at the way he treats women. (The bride-to-be is not inexperienced. She’s been married several times and has children of her own.)

I was surprised to be asked to be the “best person” at the wedding. I accepted immediately, out of a sense of fraternal duty, without knowing the bride well or even supporting the marriage in my heart. I’ve regretted it ever since. Is it too late to back out?

GENTLE READER: Yes. If it helps, Miss Manners suggests you think of your charming behavior at the wedding as a living demonstration that some members of the family honor their commitments, even uncomfortable ones.

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