Dude, I don't know all the ins and outs but having been on the recieving end of a breakup myself, through which I have sometimes felt suicidal, I know this much: if you never speak to her again it won't help her, it will probably hurt more. It's not the boyfriend/girlfriend stuff she really wants back, it's just the basic friendship. Just try being her friend but *never* give her any ideas that you might like to get back with her. It's complicated but although it will hurt her to speak to you just as a friend and not as her boyfriend, that will be better than never being able to speak to you at all.
I'm not saying she will commit suicide if you cut her out entirely, but if you show her that you can still be friends (although you should definitely avoid actual contact as much as possible since this is extremely unbearable for her) her pain will ease slowly and she will move on gradually. I know this because it's what I'm doing now. I was dumped by my ex over a year ago and continued to kid myself that we would one day get back together for months. I can't explain it exactly but, despite knowing that it would never work again and how cool a new relationship would be, I still hanker after her sometimes. That's how powerfully love resonates, I suppose.
But in spite of vowing I would never look at another girl again because my ex was all I ever wanted I'm finally moving on. Just last night I was with a new girl and it didn't feel wierd or upsetting as I always thought it would - it just felt cool to not be that guy anymore. I'm such an amateur I neglected to get her number, though
Something will click in your ex like it has in me and she will just stop stressing over you and find someone new. I'm afraid it's just a matter of time and luck. Try to find the right balance between encouraging your ex to get over you and crushing her even more. It's tricky but it really is possible. If it weren't for my ex telling me it's what I needed to do then I would still be doing my Romeo act after her.