Man i just went through this a month ago, only i was with my girl for 3 years, and she asked me to get her a promise ring, but i wouldn't, and i thank fucking god that i never did.
On the night we broke up, it was hell, it was like 6 hours of talking, and we were both eventually cool with things, but we've broke up before, but not like this, so i was like "Eh, we'll get back together", and at the end of the night when i dropped her off, we made out for like a minute. I was like Fuck yeah, we'll be back together. Then we started calling each other every few days, and once i'd forget about her a bit, she'd call, then it'd be like "Fuck, i want her back", but it wasn't happening. So eventually i had to say "don't call anymore, not for a while". So we set it up so that i'd call her back in a month. But 2 weeks later i was like "Man, i'm feelin good about this, i think i'll call her and tell her that i wanna start tryin to hang out cause i have no feelings for her",, so i call her, and she's like "Ryan, your not supposed to call for a month", i was like "Well it's been just over 2 weeks" blah blah blah,,, then BOOM!!! She tells me she met another guy,,, 3 years of her telling me how much i meant to her, and thinking about the future so much, how i'll be in her heart till the day she dies, and then 3 weeks after we break up she's already with someone else??? What the fuck did it take, 1 week for each year we were together for her to get over me??? Thing that hurts is, i know she still has feelings for me, only i'm now stuck alone and she's with some guy who knows about how we were together for so long, and he's probably saying all the "right things" to her to make her feel good, and makin it easier to forget about me. Well fuck man. I've been so bitter, i mean just look at some of the shit i posted.
This is my advice to you, and i'm so serious, try and think HARD about everything man, think HARD about it. Because my ex said she wanted more then anything to be friends, and how she was definatly NOT gonna be in a relationship for a LONG time, and she stressed that a lot. She fuckin lead me on hard man, really hard, and i'm a fucking mess today because of it.
So seriously, either sit down with your ex and try and work things out, find out how you both really feel, and if you wanna try it again, do it, but if not, stay the fuck away from her and move the fuck on man!!! MOVE THE FUCK ON!!!! It's not worth feeling the way i do at all. Start gettin out there and meeting as many girls as you can. I'm not saying fuck all kinds of diff. girls, just get out there and meet em, go out to dinner with girls just as friends, it's nice to just have a girl around as company, because i find their a lot easier to talk to about stuff then guys are. But man, MOVE ON!!! stay the fuck away from her. And no matter what, when you see her with another guy, it will kill you, it'll fuckin eat your insides right out. I told myself from the beginning of the break up theres another guy just so it wouldn't hurt so much, and fuck it hurts! I haven't seen them together, i just know she's with some guy, and he's a little french fagget, skinny guy, but he's "Nice", well isn't that fuckin special?
I'm sorry dude, i'm just still REALLY bitter,,, you should read some of my posts, and hopefully you'll see that my depression isn't worth yourself going through it. But no matter what anyone says, you gotta decide what's right. I'm just sayin this JUST happened to me the night before new years, so i got a pretty good feeling what your going through. But as much as you think you know your girl, her way of gettin over you might be to forget about you and get another guy, that's what my ex did. And now i'm left alone wondering so many things and thinking of things. Just no matter what either, DON'T think too much, just try and think about her as little as possible, and when your alone, keep yourself busy and your mind off of her, take down ALL of her pictures, and put every note or card or anything she's ever given you in a box and store it away so you can't get to it easily.
Life is a piece of shit sometimes, and some of us end up on the stinky end. But man, if you keep away from her and try and move on, she'll know if she gave up a good thing or not, but just keep in mind how you feel about it all and if you really wanna risk going out with her again.
Good luck, seriously, i hope you achieve happyness out of it all... just don't end up like i have man. Keep your head up and keep smiling and don't show desperation to her because she'll use that as a tool to take advantage of you.
My buddy said something to me that is so fucking true (and i'm sorry to girls, i'm just bitter)...
Women are like fuckin monkeys man... they'll hold onto one branch until they can grab the other one, and when they do, they let the first branch go. And it's so fucking true.