Complex ready made family

So my fiancé and I have been together in a loving relationship. For quite sometime. He has a child and I am coming into the marriage childless. I feel like he’s kinda put me in a pickle having a relationship with his daughter. He is concerned with how his daughter will feel as a stepchild and doesn’t want her to grow up feeling the way he felt as a stepchild child. Completely understood, I’ve never been anything but super nice to his daughter. In addition, his belief is that people treat children that aren’t their biological child differently than they treat their own child/children. This I’m concerned with…he wants me to have a close relationship with her though she’s not interested. I’ve taken a step back as a result and told him I’ll let her come to me when she’s ready if that would ever come. I’m not in control of that, I feel he’s really pushing it for himself and not for the best interest of his daughter. She has a close relationship with her mom and him. I think it’s best to stay out of a parental role that being said in addition due to what he feels about people feeling differently when the child isn’t their biological child. It puts me in a complex situation to get involved at all with opinions/ advice and especially in a parental role. Any thoughts?