I second what Freya said, and speaking from experience, too. If only one person remains in love (in this case, me) then it won't work out. Having to go through the fact that she would give someone else a chance over you every single time truly hurts. I was good friends with my ex when the relationship began, and while it took months for me to get over her after the breakup, she helped me through it. We've had our fights more often after it ended, but our friendship remained strong. We may not talk as often as we used to, but she knows I'm there for her if she needs me and vice versa. So it is possible, though difficult, to stay friends if you both make the effort to.