The "other" mom aka stepmom

Leah
I'm normally cool with my ex-husband's new wife but some of the things she does bother me. Like forcing the children to call her mama "her name" and me mama Leah. I am THE mom so it's just "mama." Geez, I didn't raise my kids to call me anything else for the past 11 years.
  
Anyway, what got me was the kids had a school event last night and she said, "there's 5 of us and there's you" when we were trying to figure out the number of people were there in our family. I thought, "you cannot isolate me from MY children, lady." 
  
Normally, I'm not offended by things she does and she is normally great with the kids but she has a LOT to learn about being a parent. Let's just I get along with her more than I do with my ex-husband.