How to hold my feelings back

well im still in love with my ex, we prevously split up 2 1/2 years ago and I just cant get him out of my head, when I listen music hes there and it seems like hes going to be there 4 eva. we had a 6 months relationship and it felt good and because I went out with hes mate before him he mate was trying to split us up because I wouldnt have sex with him so he told him. after our relationship ended we kepted on havin sex and going out, splitting up but it was fun 2 me but he kepted telling other people I didnt mean anything to him and calling me a slag, slut but you name it he said it and also he started to call me a black slag and stuff but stupiid me still came running back. then he fount out he was moving to northampton and I was sooo upset I could of died and he came back to london but not all the time and when I kept seeing him go I would start to cry for time. I need help because im planning to get him back but I dont know what to do and can my feeling hold me back when I see him to just at least say hi to him. help please I need answers asap please