As a Family law attorney, I often see step-parents, especially step-mothers, struggle to make a meaningful connection with their spouse’s children. In my practice, the most succesful situation that I have seen was where a child refused to eat the healthy food preparted by her step-mother, preferring the snacks anmd processed fo0ds ofered at her mother’s house. The step-daughter had a medical condition that was greatly improved by proper nutrition. One day the step-mother took the girl, then six, to several different thrift stores and thy selected dishes of different colors and made agreements that if green beans were in t4he blue bowl, the girl would eat them, just like salad in the painted red bowl and so on. The step-mother made a mspecial place in thr kitchen for the dishes (father and daughtert had moved into what had been the step-mother’s home) and no one else was allowed to eat from those dishes. Twenty years later they have a healthy and loving relationahiup as the young woman does with her mother.
Of ciurse, not all step-parent-step-child issues can have this Disney ending but a recent piece in the New York Times offers similar hope: https://www.nytimes.com/2019/03/08/well/family/my-stepson-the-owl-and-me.html