I'd avoided posting something like this online, simply because I thought I was handling this OK but I really don't know.

Basically 3 years ago I met a girl and instantly we because the best of friends, it was weird because she was 16 and I was 21 but that totally didn't matter. We hung out every day constantly inspiring each other which lead to us being in a band together, doing photography together, everything and eventually we ended up falling in love. Apart from a few people everyone was against us and I suppose it kind of made it more exciting that it was just the 2 of us. For me I've always liked girls but held back from getting too close because I truly believed I'd meet the perfect one for me and with her I did. I guess things started changing about a year and a half ago. I'd always called her beautiful but she never believed it until she became a model then all of a sudden she was invited to big parties, going to nice places and becoming very popular and I can admit I'm not the most exciting guy so inevitably she broke up with me. Her reasons were that she didn't feel the same and needed to be on her own which I could understand so I told myself I'd wait 6 months before trying to get her back and for all that time I was working on a thing that I believed would win her heart again. Basically it's a box with loads of stuff inside, I won't bore you with details but in 2 weeks it'll be 6 months and yesterday I found out she's started seeing someone. I can't stress enough how much I believe we're meant to be together but now that the new boyfriend has happened what do I do? I still want to go ahead with my plan because I've put too much into it but surely I'm just kidding myself if I think it'll work. I know this is such a cliché problem but for me it's new. My best friend (who is a girl) thinks I need to just try and move on but this ex has been in every important part of my life that whatever I think or do has had something to do with her, it just feels like if I'm not with her or trying to be I'm completely lost.

Any advice is appreciated.

Take what you can learn and move on is my advice. You say that this was the first time you actually got close and attached to someone, so it's possible that you may have gotten too attached. It's not your fault, that's how life is, and you should maybe just be a little more careful next time. If she likes another guy, then don't dwell on her. If she really wants you back she would come to you herself, and by that time, you'll probably have a girl even more amazing than her. So don't dwell too much on this girl because, as far as I can tell, you didn't actually do anything WRONG. So work on letting go and just turn this into a lesson

I know what you're saying is what I should do, it's just I've not just lost my girlfriend, it's my best friend, my housemate, my band member. I have to get over way too many things at once with this one.

It's not like your losing her forever. Just as a girlfriend. You can still be friends, I don't know what you mean by housemate though... and band members come and go in every band I've listened to but it's not like they stop talking. Start by getting over her as a girlfriend and start working on thinking of her as just a friend

Well a "box" is not going to get her back, communication, friendship and the such.

It appears she saw it was not working, ( and to be honest a 21 to16 age difference is enough not to make it work)

But you learn some lessons and start making friends more in your own age group.

I know you're right. The age gap never semed a problem, especially now that she's 19 but I guess everyone's different and changed between those ages. I know a "box" sounds pathetic, she's just the kind of girl who liked romantic things and there was a lot of that box.

When I say housemate I mean we lived together which obviously her leaving changed circumstances. Hopefully we can be friends someday but right now the thought of her with someone else actually makes me throw up.

Well it sounds like your already pretty attached to this girl. Most people give the " Get over it and move on" advice because it really works and in many cases is the best option.

Well it seems like your not ready to give this girl up, even though she seems to have moved on with her life. (like you should)
So the only advice I can give you is to try to find out how serious things are between them and see if they break up. If they aren't that serious any ways then just give her the box on your six month break up. Also if you do give her the box then make sure your not crushing her in a romantic way she probably does not feel the same way as you do. She might have buried feelings for you but I don't think she thinks about you every minuite of every day. So if you lay it on too thick it might have a negative affect. A friendly but serious conversation might do.

I know how you're feeling right now; all your friends are bundled up into this one girl; she was your everything. The age difference is what the problem is... once you're out of high school your world opens up; she was still in high school... her world is now opening up and she wants to explore the world. She might come back to you but YOU should not wait around; go discover and explore life yourself; geez you're young... lots of other girls you too could meet. You'll have to discover new friends so get going; life's too short to wait out one who doesn't want you right now. Don't listen to the love songs, watch the love movies, go to your favorite restaurant or any of that stuff. Choose new things to do that don't remind you of her. It's hard I know but you can do it. Try the rubberband trick; wear a rubberband on your wrist; when you think of her; snap it... it hurts and will detour your thoughts.

She is a gift, like a perfect sunrise. After the day has gone, the sunrise is gone. Remember the good things that came with that day, the things you learned. Mourning and pining for that sunrise to come back is only going to make you sad.