Many girls when trying to win their ex back become quite desperate and this act of desperation will actually turn your ex away. Men don't like women that are desperate and needy so don't act in desperation but instead toughen up, plan what you are going to do and then take steps to rekindle that love. It won't be easy and you may even need to make some sacrifices but it your best chance at getting your boyfriend back.
Firstly you don't want to call or text your boyfriend for a little while you need to take time to clear your head and think things through. If you call him while you are upset and emotional you often say things you don't mean, don't make a lot of sense or sound desperate, so avoid calling him while you are still emotional. Take this time on your own to reflect about the relationship and what went wrong.
During this time you want to identify your needs and your wants and also work on figuring out what it is that he needs and wants. This self reflection time will help you to find yourself again and find what it is that you want in life and in a relationship. If your boyfriend did something that resulted in this breakup then you need to decide whether it is something that you can forgive him for. If you can't forgive him then you need to let go of any thoughts of getting back together and move on. If you can forgive him then you must do that so that you don't go back into the relationship holding a grudge.
Through this self reflection time look at how you act when you are around him. Are you clingy and possessive of him? Men like to be able to provide and protect their women but they don't like women that are overly possessive and paranoid so if you have been acting this way then you need to take steps to change that. Even when you are in a relationship you need some amount of individuality and you need to let him have that and you should also have it yourself. You need to take a good look at all the aspects of the relationship and see where it went wrong and where there is room for improvement.
When you are calm and are thinking clearly and have discovered yourself and what might have gone wrong in the relationship, and then you will be ready to talk to him. Call him and invite him out to one of your favorite places that you both enjoyed going to together. Talk about the things that you have in common and the things you liked to do together. Talk about the happy moments that you had together.
Then talk about what you have been doing and what you have been thinking about. Let him know that you have thought long and hard about the relationship and that you want to work together with him to overcome any problems that you had and make the relationship work.
If your ex boyfriend is already dating someone else then don't go chasing him, if he has moved on then perhaps you need to do the same. He might not be happy with this new person and realize he has made a mistake and call you, but if he doesn't then you need to let him go. Chasing him when he is happily dating someone else will just bring you more heartache.
It is hard work to win your ex back and you want to go into it prepared and ready to work at your relationship.