Dear Prudence Photo illustration by Slate. Photo by Getty Images Plus. Our advice columnists have heard it all over the years—so we’re diving into the Dear Prudence archives to share classic letters with our readers.   Submit your own questions to Prudie here . Dear Prudence,   I’m very close to my family. I tell my parents and siblings about nearly everything and receive their support. My fiancée is not and does not. We have, for the most part, reached a compromise where we each control the flow of information to our respective families. The problem is this: We both like her sibling-in-law, and while I understand the hostility she feels toward her sibling based on their past, what I have seen is her sibling trying to rectify that past. Her parents are a separate issue, and I agree with her handling of them, but I don’t know what to do when I can’t see the malintent she attributes to her sibling’s actions.…