should maybe elaborate that this was said during a conversation between my (ex)SO and I, while we attempt to work on things. I'm finding this exact premise (which seems to rear its head often) a huge roadblock to progress and I'm unsure what to think of it.

Am I being ridiculous in thinking that this is completely out of line for her to say/think? How should I react? What do I do to smooth it over/convince her that indeed, it should be the same from both sides?