Husbands birthday cake

So it was my husbands birthday and we had his family over for dinner and I don’t know if it’s the pregnancy hormones or if I’m actually offended that when we cut the cake, he fed his mom a piece of cake and then fed me. I wouldn’t even be offended if he didn’t feed anyone but the fact that he fed her controlling egoistic ass first has me livid internally. Of course I’m in my 30s and can hold my shit together so I didn’t show any reactions but it’s her controlling nature that makes it worse. Am I being too harsh on him??