I'm afraid what I'm about to say to you will have the effect of someone throwing a bucket of iced water over your head while you're sleeping.
WAKE UP son... Life is all about pain. I've been in your situation more times than I ever wanted to be. You ended the relationship, that was your mistake. Yes, of course... you ended it for valid reasons, but now you need to realize that THOSE REASONS are why you shouldn't go back! In her eyes, (and in mine) it would appear you're 'crawling back'.
Not every woman will do this of course, but don't bet that she wont!: She will play with your heart... You've hurt her, and if she REALLY loved you, and you broke her heart... you've unleashed the 'beast'. She will attempt to hurt you AS MUCH, or MORE than you hurt her.
So mate, cut loose and run while you still have your heart. Love has it's price, and you will find someone else out there ( plenty of fish

) that will make your heart soar more than it does now.
I promise you, she is NOT the one