You took the high road and that's commendable. At the same time, I don't see much parallel between your story and the original LW's story unless you were attempting to establish a deeper relationship with your stepmother when she didn't want one.

The new wife in the original letter seems like one of those people you sit next to on airplane. You have a book open and want to read it. They introduce themself and start to make small talk. You politely explain that you are trying to read a book and are not interested in small talk. They keep on talking and get upset and think you're rude when you don't want to enter the conversation.