Hi Lion,
I've made a very similar experience some years ago, and it also took me some time to digest everything and bring my self-confidence back to old levels. In hindsight, I can say that the (budding) relationship was doomed from the beginning, as she wasn't self dependent enough to handle pressure well and I lacked the aggressiveness needed to assure her. We might have fit well if we had met at different stages of our respective lives, but as it turned out, she shied back from a promising but unsure future and picked the mediocre but well-known past. I was at a loss then, dropped away like an empty gum wrapper. I still do love her in a lot of ways, but I've cut the contact and moved on, and taken with me the lesson that being the understanding guy isn't always helpful.
I regard every love and relationship I had up to now as a learing experience, with every breakup hurtful but nonetheless shaping me. I think a lot of the hurt came from being forced to un-learn things and traits that had been deeply imbued in my personality, before being able to accept new values.
I hope that, eventually, you can also look back to this part of your life with a sentimental smile. Until then, don't try to too hard to be unselfish - I'd rather suggest the opposite, grant yourself the right to be selfish, angry, betrayed and fed up from time to time, as it's a part of the process of reaching closure.