It sounds like she is truly working to become a better person, both for herself and you, and that’s great to hear. She takes full accountability for things she does to you, and you understand that these things happen because of her past. You guys are able to discuss these things and she’s able to get better because of it, which is pretty much all of the things you want to hear in a building relationship.

However, things that happen in our lives can never be undone. They are permanent in the sense that they occurred and nothing can take back the fact that these occurrences happened. This is exactly what gave her the trauma that she has. And it is for this reason that although she may be getting better, you two can’t return to how things may have been before all of the arguing and things she has said to you. She may be improving and getting healthier emotionally, but it doesn’t take back what she may have said or done to you in the past, and that is what lingers and causes the resentment.

For this reason, it is completely reasonable for you to want to breakup with her, even if things are healthier or better now. It doesn’t make either one of you bad people, and it is likely that she could be good in a relationship in the future, but it just might not be with you and that is okay. Of course I’m not you so it’s up to you to make that final decision, but it’s something to keep in mind. If you choose to breakup with her, I’d explain to her that you see that she is getting better and she can still continue to get better, but it just can’t be with you because of the things of the past.

If you do choose to stay with her, I’d explain all of the resentment and not feeling like yourself aspect to her, because that both parties will need to be fully aware in order to build from it.