The person you have loved for so long has just walked out on you.
You are absolutely numb from shock, hurt, angry, and very frustrated that your near-perfect life has ended this way.
This is a natural reaction to anyone in your situation.
Some get very good advice, take it, and use it to their advantage, while others, no matter what advice they get, decide to chase after their ex's in the hope of getting them back, only to fail time after time.
Believe me, this is NOT the way to get your ex back.
All you are doing is making your ex really happy that he/she got out of the relationship, and has no intention of getting back together with someone as emotional as you What you really need to do is to make your ex regret the day he/she walked out on you.
You have to improve yourself in such a way that many people of the opposite sex begin to take an interest in you, and are going out of their way to get to know you.
Yes, it is difficult to do this the way you are feeling right now, but, when your ex sees just what a catch you have become, he/she will definitely feel that he/she made the biggest mistake of his/her life by walking out on you.
This is going to make it so easy for you to get your ex back.
Your ex is going to make a point of getting in touch with you as soon as possible, with the idea of getting back together again, before someone else has a chance to ask you out.
Of course, YOU have the advantage now.
There are so many people who are more than willing to take your ex's place, that you can decide quite happily, whether you want to get your ex back or not, or if there is someone else who you are more interested in.