I'm in a similar situation, only the crush lasted a few months... a decade? Holy honeysuckle, man. While I don't know your situation what I think you should do is this...
First... realize you have to love yourself MORE than anyone else. That means you have to sort of separate yourself from the "you that feels" and play a guardian-type role... you have to look out for the interest of the "you that feels" and pull him out of any situation that is destructive to his well-being. This may sound strange but I'm doing this right now and it is healing me a lot faster than just letting time go by.
She has obviously caused you pain whether directly or indirectly, intentional or otherwise... know that she is not worth you suffering because you can't have her. She's probably off living her merry life... move on and live yours. If you don't you are giving her power, control, and your nuts in a small glass jar.
There are women out there who won't give you all the negative feelings you're experiencing... only the positive ones (for the most part.) You just need to start the search.