Just found out my ex of less than a month went back to her abusive ex after breaking up with me.

This girl (21F) and I (22M) had that this great thing going and she said it was great going against what her ex liked and weeks later she decided that she needed to go against me and got back with her ex. Did I do something wrong? Did she want to get back with her ex from the beginning? All she seemed to want after breaking up was someone with her, while I was 60 miles away. Then she got back with her ex who was SUPER abusive to her, then only admitted the least. I really want to get back with her, because it's all I feel I might find in my life. Please Help!!! I DONT KNOW WHAT IM DOING ANYMORE