Oh, the heartaches we feel when we experience a breakup. We might even ask ourselves why it couldn't be called something less permanent. The breakup word seems so impossible to fix. This gets us into victim mode, and instead, we can choose to put some work into the making up part.
If getting to the saving the relationship part can seem possible, then know that 90% of the time it is possible. Step one allows for some perspective about what happened to cause the breakup. Once that is determined, a choice to learn from mistakes made allows for growth from the experience.
Some behavior changes may be in order. For instance, If your past actions were too much for your ex to deal with, then it is a good idea to identify them. This way, if the situation arises again, you don't repeat the old behavior. Part of getting perspective on the cause when you experience a breakup is learning how to deal with the present. This helps get out of the victim mode and work on reviving the relationship to a long term basis.
Step two is to get okay with yourself. This means to show some strength without the ex. Don't show neediness. Granted, we all may feel like we can't go on without our ex, but it isn't necessary to ensure our ex and everyone else that we aren't just fine by ourselves. Showing self-confidence, comfort in our own skin, gives a better chance at making up.
Remember, whatever event(s) that happened in the past to cause the breakup cannot be changed. However, you can change; your attitude, behavior, and rekindle the relationship if you want to. Trying to change or get back at you ex simply doesn't work. If your ideal scenario is to reunite, then start by giving yourself some time getting comfortable and self-confident without your ex.
The making up part takes some work. Get the specific cause or causes, because sometimes the breakup is accumulated from the time in the relationship when action was or wasn't taken, and that builds. Then begin to look at the possibility that you can change for the better, and spend time accepting the breakup.