Simon, I agree with all the excellent advice you've already rec'd here. Something of a "lightbulb" did come one, though, when you said you had shared some of your personal history and issues with her, after which she began dating someone else, saying she "couldn't handle it." I've done this in my dating past, and experienced the same kind of reaction. In retrospect, even though it felt natural and "right" to share such deep feelings and history with someone, I now regret doing so, and will not do it so soon in the future, if and when such a relationship should occur (at least not so soon).

I think, if you want to pursue contact with this girl, you should do so as friends for a time, seeing how she responds to you in a more neutral and less potentially emotional situation.

Something else you related, with which I totally identify and recognize, is the long time spent in recovery from hurt, and the reluctance to place yourself in this precarious emotional vulnerability again. I'm much older than you, and having a history of family abuse (not sexual, but physical and emotional), and a very poor example of what a healthy loving relationship is about between men and women, I also have had a very hard time recovering when it failed, spending years to work thru why it didn't work out, though i felt I put everything positive into making it work.
This disproportionate attachment to people who rejected me, I feel, stems directly back to the history of abuse.

I've rambled here, but my reason for sharing this with you, dear Simon, is to tell you, first of all...you really are very young. You can have a happy relationship with a girl, I feel certain. Just take your time. If this girl is agreeable to friendship and further contact, just try to enjoy it and experience the company. If she is not, please don't find yourself dwelling on it.

Love
Patty