Caring is Sharing?
It looks like this couple really likes carrot cake. One member of the couple even took the time to mark how much of the cake is left for them. It seems their partner already ate half the cake. This is actually a reasonably good way to deal with things between couples, especially when favorite treats are involved.
Yes, once you’re married, you pretty much have to share everything with your partner. Besides, never mind conventions, you’re supposed to want to share everything with the people you love, right? Well, you have to draw the line somewhere, and for this couple, the line ends at this carrot cake. This person is right – their partner already had their half, and they should keep their hands off the cake.