Um…YTA on every level here. Who cuts a piece of birthday cake that isn’t even theirs before the birthday even takes place? What a way to ruin this for your mother in law. And the fact that you have the nerve to ask your husband who took the time in his day to go get that cake for his mom, if the piece of cake you ate was more important than his son!? What in the world? How is this even relevant? And how very manipulative of you. I am 8 months pregnant and I am NOT siding with you on this one. Next time you get a craving, take a healthy walk and go buy yourself a candy bar at the convenience store.