Being in love with a guy and having him suddenly tell you he wants to end the relationship can make you desperate to get him back. But, that desperation is what could keep you from getting your ex back. As long as you let him know how much you love him, he knows he can have you whenever he chooses. Learn how to show your ex boyfriend you don't care and make him crazy for you again.
If you try to stay close to him so he will not find someone else, you are apt to drive him into another woman's arms. That should give you a clue of how to get him back. Sit down and think of what your instincts tell you to do in order to get him back. You will find that you want rush to the phone and call him and tell him you cannot live without him. You will want to send long emails and text messages containing love poems and messages of your undying love.
Now that you know what your instincts tell you to do, you should do just the opposite. Do not have any contact with him at all. Act as if he does not exist and take up your life as it was before you met him. Act as if you don't care and soon you will find your ex boyfriend being crazy about you again. This might be hard to believe because he won't communicate with you, but it will happen.
If you would have followed your instincts and showed him you loved him and needed him, he would have kept rejecting you. But by acting as if you don't care, his ego and pride are hurt. By not trying to get him back, he will feel you are rejecting him. Since men always want what they cannot have and they do not handle rejection well, you will have his full attention.
But a man can be crafty too. So he will probably send you an email, asking how you are doing.