Marrying a person does mean, for better or worse, marrying into their family. Sometimes this just means more people around for the holidays and sometimes it means having to deal with some of the most entitled and delusional people showing up at your house.
A woman shared her horrible encounter with a MIL who would just show up unannounced and start making demands. After her husband failed to back her up sufficiently, she decided to have a sitdown. Fortunately, we all got a little closure, as she later shared a sizable update on how the situation was resolved.