Hey CG, I am sorry to hear about your dilemma. Let me share a personal experience with you.
My first relationship was with my childhood sweetheart. She was from my church and not only did we like each other, but a future looked realistic between us. However, she was not a pleasant person. I was in an emotionally-abusive relationship which costed me my friends and nearly also my career. Eventually, I had to walk out of that relationship, even though I was the one who had invested more in it.
A year and a half later, she got in touch with me in order to restart things. She profusely apologized for her behaviour and she was willing to give me the time and the space to get back with her. For a couple of weeks, I did give it a shot. But that was when I realized that the hurt from the past was so strong that it held me back from committing to the relationship for the second time. I had to sever things once and for all, with a heavy heart, after realizing that the best days of our relationship were already over.
I can relate to your dilemma and I think I understand why you want to go back to her. But here are two reasons why I don't think you should do it - 1) If she took a lot out of you the first time, she will probably do it again the second time too; 2) Even if you give in and get back with her, there will come a point when you realize that you do not feel the same way about her anymore. The feeling that you don't love her the same is worse than not being with her at all.
Take our word of advice and do not make that mistake, my friend.