When all looks lost and you want to get back with your ex, the first thing you need to believe is that it's not hopeless. As long as at least one of you wants to save the relationship (and obviously you do, or you wouldn't be reading this), there's hope that it can be saved.
The first key to getting back with your ex is to leave them alone for at least a month (if at all possible, leaving them alone for longer than a month will work even better). Stop all contact with them right now and give them time and space to think things through.
A lot of times during a breakup, people say things in the heat of the moment that they really don't mean and take positions that they wouldn't normally take, and if you seriously want to get back with your ex, you have to give them time to realize this on their own.
If you don't give them time to think, and you push your ex into getting back together before they're ready to even think about it, you're only shooting yourself in the foot: you have to realize that, by walking out on you, your ex sent a very clear signal that they needed time to think and that they want to do it alone.
You have to respect that.
If you're concerned that you've totally lost your ex because you've heard they're dating somebody else, remember that most "rebound relationships" don't last very long. Chances are your ex is dating that other person as a way to try and convince themselves that your relationship is really over. And just the fact that they're trying to convince themselves that your relationship is over means that even they're not sure it really is.
Do you see that?
The fact is that rebound relationships rarely work out because the person on the rebound is still emotionally attached to their ex. So don't waste time worrying that all is lost just because your ex is dating somebody else for the moment. The simple truth is that your relationship is about you and your ex, not about your ex and somebody else.
Give them the time and space to think things through, let them cool down, and don't do anything to alienate them, and you'll find they'll be a whole lot more open to the idea of getting back together with you.
