The point about re-evaluating expectations after breaking up really resonated with me. 6 months ago I broke up with my girlfriend after months of being unhappy with certain things in the relationship. Now, 6 months later, I can say that this was one of the worst decisions, if not the single worst decision, I ever made in my entire life. Turns out, that relationship was pretty ideal for me in many ways, and I should have tried to resolve the issues I had rather than bottling up my dissatisfaction and letting it eventually boil over. I now have a much better idea of what I want out of life and what I'm looking for in a relationship. I just wish I could have learned that lesson without causing someone so much pain and then going through so much pain myself.
People change, life is long. We are all struggling together. Have hope.
Your ex is still out there. Maybe she feels similarly about you.