Congrats on striving to overcome angry out-bursts.
My take on things is that your W is enjoying the sense of freedom and at the same time...she's seeing you at your best. However, it has been a very short time and she is not convinced that those changes will stick. It takes some time to instill new life changes. It's like having to diet b/c of health reasons. Almost anyone can stay on a diet for a short time, but when you think about doing it from now on....it ceases to be a diet and becomes a new eating behavior.
She could be seeing a certain amount of eagerness, hope, expectations when you are together. That is why she suddenly seems cold. She doesn't want you to get your hopes up and think everything is honky-dorey. If the two of you went back together right now, it would be very easy to fall back into those old habits. It's not that hard to change, but it is hard to stay changed.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!
