Is it okay to call a step-parent mom or dad?

I have a three year old step son. who calls me momma. When his mom found out she threw this fit about it. But she lets him call her girlfriend mom all the time. My fiance said that he can call me mom if he wants. But I don't want to cause problems that don't need to be there? Should I let him call me momma or no?


Don't feel bad

Let him call you whatever he feels comfortable with, he obviously sees you as a parent, why deny him that. It is about him, not her, at the end of the day, he's the child and is...