This is a very important thing that has to be pointed out again. Did the OP ever put down boundaries? If so were they clear or muddled?
We never did discuss boundaries, which I believe was the issue. She said that she wanted me to stop making unwanted gestures, and I was only half aware of them (more spring to mind as time passes; makes me wish I never even shook hands with her in September of 2009). My choosing to do this stemmed from the idea that we should not have to have a discussion about it, nor should she be the one to keep bringing it up against me because it could only end a lot worse than it does now. I'm the one choosing amputation over her band-aid
And didn't do shit about it. And he stayed under the false guise of a friendship he had no intention of ever having. It's not my job to walk on eggshells around someone if they have feelings for me and I don't have them in return, they can leave if it's too hard for them. If they opt to stay, they're choosing a friendship and I'm going to treat them like my other friends and they can still leave whenever they want to. The point everyone seems to be willfully ignoring is that OP didn't want a friendship, he wanted a relationship, so his entire presence in this girl's life was under false pretenses.
OP lied and was selfish. He isn't a victim.
I'll clear this one up, too. Did it start that way? Yes, I will admit that. I was fresh out of high school, still wearing fedoras, still believing that girls only every wanted the asshole to date.
But thanks to a post-secondary education and an actual discussion on the subject of feminism beyond 4chan, I grew up. There was a time, brief it may have been, where I did consider this a purely platonic friendship. But I guess that illusion was bound to shatter eventually when she said those words to me. I can say with near certainty that was the tipping point, that she would go out with me if she wasn't dating that other guy.
At which point, my proper response was "Well, I would never choose to come between you two." Hell, when they were first on the rocks I was the one giving her relationship advice when she was crying in my car because I was really wanting her relationship to work out.
Unless of course this is all a lie and my subconscious was deliberately sabotaging me?
Regardless, I do honestly feel better about cutting this off. If it must be permanent, I accept that, but for now I'll live under the assumption that one day we can come back to this, start a fresh friendship that starts and remains platonic. If that must not be for a few years, then I understand. I am the only one who can make that call, and I know I have to do it with utmost objectivity.