Bigdu,
You let her go. Assuming you told her that you still want her, then she has made her wishes clear, she wants other people. She is in the power position here because she determines what the status of your relationship is, that is a sucky place to be for you.
A word to the wise would be to invoke the "as if" rule:
You act as if its totally over and she is nothing more than an acquaintance that you are warmly friendly to when you see her. You don't call her, how often do you call an acquaintance? And you don't spend anymore time with/on her than absolutely necessary. The less the better. Why be her emotional support if you are getting only pain from it?
Date as if she is not in your life.
Go out with your friends and plan activites as if she isn't a factor.
Be light and flirty with her but nothing else. And if she asks you sincerely how you feel, tell her that you still care for her but that you need to live your life. And you are respecting her wishes by giving her space.
This is actually the best strategy that you can use to get her back because it tells her that you still like her presently, but are out there on the market. And she will think you are even marketable than you might really be, because she liked you herself.
If you feel guilty or hesitant about having fun, remember she is.
Also, its a sad thing, but often if a person feels really secure in the relationship they will want to experiment because deep down they don't think the other person will actually leave them. So they can have the best of both worlds: new exciting experiences, emotional security and a fall back if they don't find anything else. ITs not fair but it happens. But if you show you are perfectly willing and capable to move on, it forces her to rethink what she is doing.
Also, girls can smell deperation and they don't find it attractive.
Good Luck.