...and continuing with quotes, you have these little numbers by W.C. Fields:
"No doubt exists that all women are crazy; it's only a question of degree."
"A woman drove me to drink and I didn't even have the decency to thank her."
And reading this thread for a while, all I can say is I'm sorry, but in the end it's her loss, and from what I read, you did the right thing in breaking up. She may come back looking for you (once she misses having someone being nice to her) or she may not, in the end it shouldn't matter to you now. Keep things polite, but don't go looking for her .
I agree with what Tender Vittles and most of the others here have stated; there's a line between being sweet and supportive and letting a girl walk all over you. And I also agree with Scot that we humans can be so ****** up when it comes to love.
I've also been "the nice guy" and I'll probably screw up a few more times, relationshipwise; at least I hope I make new mistakes, or repeat previous mistakes in a lesser degree, 'till I find the right one. In the end I am who I am, but I can change the way I go about this game and be smarter about how I express my intentions/affections. I was a bit alarmed that you seemed to avoid all serious friendship with any other women so as to please her, that shouldn't happen!!! She should trust you enough; what whould have happened if you got a great job where you had co-workers that were attractive females (besides being one lucky bastard)???
If I were you right now, I'd: go out with my pals, play some videogames, go to a race (just don't participate if you're a bit emotional), watch a mindless action movie, hell I'd even go to a strip club the next week or something if I suddenly had the physical urge to see a woman. Keep your mind off her, and be nice to any girls you might stumble upon... who knows?