I want to leave my so, but I'm scared of being alone and I feel I have become too comfortable
Why are you so scared of being alone?
I want to break old habits but I'm scared of being alone.
It is understandable to be afraid of being alone if you leave a relationship. You have become comfortable with the arrangement. But you will not better yourself if you stay in a relationship that you do not want to be in.
I need to talk to her and try to convince her to come with me.
You should not try to keep her if you are so unhappy. You can make it on your own and I think it would be good for you to learn to enjoy your own company again. A break can put things in perspective and get you into a healthy mental state.