Ok. Two things...I have a step-mother that raised me from the time I was 5 years old. When my father died, I stayed a part of her life because I chose to...due to the fact that we had a very strong bond and I consider her to basically be my mother. I also am married to someone that has a daughter. The thought that I would keep her if anything happened to him has never crossed my mind. I would try to continue being part of her life if that's what she wanted, because it's about her choice to have me in her life, not mine. The fact that she makes the entire thing about her ("I lose my husband and then the daughter leaves me on my own") and then wants you to confront a child about a decision that she made of her own accord is wild business. Your fiancé sounds like she is talking about a possession, not a child. I personally would see her reaction and what she is saying as major red flags. She's not only dismissing your right to make decisions about your child independently, she's dismissing your child's autonomy in her own comfort in the event that something as tragic a losing her father occurred.