Broke up because I was unhappy

After feeling unhappy in the relationship for a long time, I broke up a few months ago.

This was very unexpected for her and she blames me for not giving a proper reason. It's true that I chose to not give any examples, I just shared that I started to feel unhappy in the relationship and that it didn't feel safe/closeby enough for me anymore to give more feedback.

This was also because on previous feedback she did not respond very constructive, she gave it all right back to me. I let her know that I would like for her to look a bit more critical to herself, but that is too abstract for her.

Is an unhappy/unhealthy feeling in a relationship enough reason or is she right that it was rude to just keep it at that?