I need advice on how to move on.

[Xiahou]

We've had this song and dance before actually in high school.

Maybe it's just me, but I think you have the right to be a little angry here. Don't get me wrong, you don't want to rage out and do anything stupid- but it does sound like she was using you a little and I agree that cutting contact is the best course of action.

The way I see it is that she wants to be free to have flings with other guys as she sees fit, but still wants to keep you on the back burner as a "friend" when she wants the emotional support that she won't get from her dalliances. That's a very one-sided relationship. She's getting everything she wants and you're being torn apart emotionally by it.

Maybe she isn't even consciously doing it, but I think you're being used. Cut off contact. Otherwise you'll see the same "song and dance" over and over again.

Edit: Also, to echo what others have said- find other things to occupy your time and energy.

[Peasant Phill]

@a completely inoffensive name

Some simple advice from someone who had a 12 year long relationship ended and never saw it coming as well:
Throw yourself on other things to do. Call friends and go out as much as you can. Start a new hobby, something you were always interested in but never started with. Meet new people any way you can, ...
Just keep busy and don't dwell on what was. This is your opportunity to have a better life.

[The Lurker Below]

If you love someone set them free,
if they don't come back shoot them.

Alright you're on the right track with the whole cutting off all ties idea, but relax, enjoy some life first, and then pull the trigger. Freedom for just a few days ain't really freedom at all. Go enjoy some life your own self, and play friends. If you've really been friends for so long, playing the part for a few weeks shouldn't kill you.

And that brit that gave you the advice re: StarCraft was absolutely right. Making friends online is too damn easy. Anything that comes easy has no real long term reward. Step up your game and go socialize with real life hooters. Use your body now while it's full of energy. There will be plenty of time for easy chairs and games after your kids have worn you down.