DEAR ABBY: About 20 years ago, my mother-in-law confided something shocking to me. Some background: My husband has two sisters. One is a year older and looks just like him. They both resemble their dad. The younger one looks nothing like the other two or their dad.
My MIL told me she and her husband stopped having sex after my husband was born. When I asked, “What about the younger sister?” she said she made a “mistake” with someone. We talked, and I suggested how important it was to tell the kids about this, but she never did. She always told people the younger one looked so different because she was so many years younger than the other two.
