If you want her back here is what you'll need to do:
Act indifferent. It shouldn't matter a single iota whether she comes back or not. This may sound counterintuitive but the balance of weakness always lies on the person who commits to the act of pleading for the relationship to stay.
When she does contact you act like you're too busy. Even more counterintuitive but it'll only spurn her desperation.
Do not contact her for 3 weeks. I assure you alarm bells will be ringing in her head.
Talk to other girls like you are dating them. If you can make your mind believe that you're in greener pasteur you'll be able to look at this relationship with the ex more accurately.
Everything you do during these times is critical. Your inability to see reality accurately is whats the problem. This is why others outside can often see things so clearly while you are caught up in micromanagement and the details. Remember, 80% of what you think about or reason as good ideas to beg, plead, etc. is complete nonsense. 20% will make some sense but you'll only be able to achieve that once you've done the above. The chances of you wanting her back after this though is unlikely, especially when you're a man of options.
Be slow to fall into friendship; but when thou art in, continue firm and constant.