HELP STEPMOM

My feelings are EXTREMELY hurt. Before I go into what happened here is some background info

-Three Stepchildren

-dad has full custody

-bio mother has only had supervised 2hr visitation for 2 years.

-bio mom is ex drug addict

So while outside today, scrubbing poop out of Brad (stepson) baseball uniform because he had stomach virus 😒😭 my boyfriend (we are getting married just waiting till we getting settled in our new home with the kids) stepmom walks outside and proceeds to tell me that I do not need to go to his baseball game tomorrow because his biological mother is going to be there. I have NEVER missed a practice, game, anything for any of the kids. She says she doesn’t think it’s a good idea because she is manipulative and will act nice until a couple weeks later and make a deal out of it. And then tells me that I am not forced to do anything for the kids and that if their biological mother was able to she would be here going to games and doing hair for the daddy daughter dance...my heart broke. She is not “able” because she chose drugs over the children and lost her rights. So if she could do all of those thing why do I take them to school and pick them up everyday? Why do I help manage the oldest diabetes, why am I grocery shopping, and scrubbing poop out of baseball pants? Also, the youngest sibling calls me mama. When she started doing this I made SURE to explain to her that. Her biological mother was her mom and that she grew in her tummy and not mine and that when her daddy and I get married I would be her stepmom and that she could call me whatever she liked and did not have to call me mama. At bedtime she started crying for mama and her grandma come in and yells at her saying “you want me to call ******? Because that’s the only mommy you got” I was livid. I understand that we are not married yet so I’m legal terms I am not stepmom yet but this had me pissed. I have called my StepDad DAD since he married my mother when I was 7. He feeds me, clothed me, made a home for me and that is a DAD. Not a name on a birth certificate. Any advice or comments would be helpful.