HE CALLED ME CRUEL😨

Hi thanks for checking the post!

so i am a mom of 1 and step mom of 2. the 2 older kids have different moms and one I get a long with and the other I really don't. now one of the kids (the middle child) has been acting out really bad at school and he kept asking for things to do at home and I told him no and we get in the car and he wanted me to change the music and turn it up numerous times.and I told him no as his father and I were talking.so his dad tells me "you don't have to talk to him that way."im like "what are you talking about im putting a Child in there place he needs to calm down." so he says "you know what your cruel" and that's were the conversation pretty much ended.he has told me that im to mean once before but he's the one that will let the kids get away with anything. I have to be the one have a backbone and say NO to all 3 of the kids. but it really hurt when he said that I need some advice please....