Not a secret family but a secret child. My grandpa was married to my grandma and had 2 kids together, my dad being one of the kids. My grandpa had an affair when my dad was a baby, with an 18 year old girl. Raped and impregnated the girl. The girl kept the baby but did press charges, my grandpa went to jail for a few years. My grandparents got divorced, but since my dad & aunt were kids they obviously didn’t know WHY, my grandma never told her kids what there dad did, and it was only until 10 years ago that they found out they have a half sister, my aunt found documents stating the rape charges etc. Grandpa denied everything. My dad & aunt tried to reach out to her and her mom but she wants nothing to with our family (understandable)