I'm mind reading, but I think in her mind if I got rid of the dress then it wasn't her doing it, it was me and it would make it easier for her to deal with it being gone.
I think that's a very good point. Let her deal with it. Would you keep it forever?
There are moments in this life when you are so confident in the rightness of your actions, that not even for a second do you consider the option that you might be wrong.
