You keep stating the ending of your M was a matter of a misunderstanding. You are minimizing it to an extreme degree. Your M did not end because of a simple misunderstanding.
Also, no matter what we say, you keep saying you should have known the severity of how she felt and that she was negligent in letting you know she was going to leave if you don't change. She let you know what she needed, you didn't listen. Please, in the future, don't only take action unless the consequences are severe. Take action BEFORE they become severe.
We cannot reiterate this enough. for any future R's.