They Clearly Agreed I'd Be Their Stand-In, so How Did You Secretly Give Birth to My Child?

"The contract expired a month ago, when are we going to get a divorce?" I asked my wife, holding my two-year-old "sister-in-law" in my arms. She laughed, "Divorce is fine," my wife said, pointing to the baby in my arms. "You should ask our daughter if she agrees first." "Or are we not getting a divorce? Can you bear to let your own daughter be without a father?" I sneered. This is clearly her aunt's daughter. But the paternity test clearly states in black and white: I am the child's biological father. I'm going crazy. When have I ever had a relationship with her? She smiled and handed me a glass of milk, just like every night. "Drink it, maybe..."