I think you still have some work to do. You began your letter by saying that you wouldn’t talk negatively about your ex. Then you followed up with a list of all the things she did to hurt you. Whether or not everything on the list is true, you are the one who decided to get violent.
Healthy couples who have big problems talk them out or take a break. They don’t physically and verbally hurt each other.
I’m glad you are both in therapy. Even from your short letter, I think you both need to do some growing before you are ready to be in a relationship. Eventually, if you both want to try to save the relationship, you might try some couple therapy to see if you can forgive each other and learn how to be a team that can share the responsibilities of a relationship and work out problems in a loving and supportive way.
I wish you well.