DEAR ABBY: I am a 57-year-old man who has been divorced for eight years. (My ex-wife was the one who filed.) I recently reconnected with my ex-wife’s sister, “Edith,” whom I hadn’t seen in years. We began a friendship, which has evolved into a serious relationship. My ex is having issues with our romance and has been trying to turn friends, our grown children and our parents against us. We are bot…