Trying to become a part of his life by going around or doing some activities with him. And hope you still have a chance to turn it back anymore. I personally think, going back with an ex isn't a good idea.
Well, when you broke up with him you felt that he's not the one. So, now you just had this memories you had lived together back on your mind . You miss him you want him back again but that's not the right thing to do . Just move on