I will make this short and sweet. The simple answer to that question is ..
Be happy and Live your life.
Go out, force yourself if you have to. Live life large, put him. at the back of your mind. It may not be easy at first but you can do it.
Once he realises you are not pining for him, he will come looking for you. No one likes someone who clings to them or ‘stalks’ them, or even bother them. It causes further distance.
Therefore let go, live your life and if its truly meant to be, he will come looking for you once he finds you are living happy and large.
Ensure you let him know subtly (not directly) that you are living life. Post photos on your social media, hang out with your friends, flirt with other guys if you have to.