Care and Feeding Photo illustration by Slate. Photo by antos777/iStock/Getty Images Plus. Our advice columnists have heard it all over the years—so today we’re diving into the archives of Care and Feeding to share classic parenting letters with our readers. Have a question for Care and Feeding? Submit it here . Dear Care and Feeding, We are very fortunate to have three sets of grandparents that are all loving, kind, and very involved in our 6-month-old daughter’s life. My parents are divorced and both remarried, so we have some “step-grandparents” in the mix. Everyone gets along, and while my in-laws live far away, they visit often and get weekly updates on the baby. The problem is my father’s wife. My dad got remarried when I was in my early 20s (I’m in my early 30s now), so while I’ve known his wife for a long time, she was not involved in raising me. She’s very sweet but she has a major problem with anxiety.…