It's so frustrating when my SO tells me to tell him when he is doing something wrong with the baby…

It's so frustrating when my SO tells me to tell him when he is doing something wrong with the baby but when I do he bites my head off and gets frustrated. Like sorry I'm with the child 24/7, I can tell exactly what he wants. So then baby sits there upset because he won't listen to me. The saying is true "mother knows best"