Giving by your way of typing, I highly doubt that she is your last love. You are very young and you will have lots of other girlfriends. I'm sorry to tell you that when someone cheated once, she will do it again. She got what she deserved, being with a guy who also cheats. She will face the same consequences and pain that she caused you by cheating. But still, blocking you on Facebook proves that she is not into you anymore.
And maybe that is not such a bad thing. Why would you want to be with someone who cheated on you and will do it again? Once a cheater Always a cheater, dear.
There will be much and much more (right) girls for you. Try to forget about her and search for another one. It won't be easy, but the right girl for you is out there and it is obviously not your ex.
Good luck, and don't give up!
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