How do i forget bout my ex?

his grandmaw didnt like me cuz she saw us makeout so he broke up with me n for six months we still talked n he broke my heart wen he dumped me n i still love him even after he lied to me n went out with one of my friends n i was depressed for almost a year after he dumped me n im ok now but i still love him n i knw its stupid but i just cant turn it off n i dont know what to do, plus ive started talkin to one of my guy friends n i want to move on from my ex cuz ive dated zero people sence him n thts been like a year cuz i think its wrong to date someone wen u love another, n idk wat to do HELP