It is wonderful to hear how beautiful your love is for each other. No pun intended, it sounds magical.
Being in a painful relationship is often the turning point. Once betrayed and abandoned they often have to rethink their life and choose a course of action that, at the very least, moves away from that relationship.
What sounds clear is that your girlfriend has not only moved away from the horrible situation she was in, but moved toward you. This is a high degree of resilience, which is directly responsible for the two of you getting together. If that other relationship hadn’t been so terrible she wouldn’t be with you. Her past pain was a direct motivator for her to be in your life. I understand why you would dislike him, but his miserable treatment is the primary reason she is with you. Your friends (and hers) are likely to be happy you both found each other.