Just know it will not end anytime soon, he may stay away for a while but he will come back again, the only way for him to stop is to find someone else, someone he will love or atleast like...the only thing you can do at the moment is to ignore him.
Believe me, no one like to be ignored, he will get mad, feel stupid and stop following you, but as i said, he will be back unless he get a replacement, and not just any girl, but the girl should real uproot you from his heart.
Ignore him, move on...there is nothing more you can do...Pole...