It can take a long time to get over someone. I know the feeling. About 4 months ago my boyfriend of over a year broke up with me. I was still in love with him, and still am and it really broke my heart. I felt even worse when I found out he'd met someone else, and was really upset for a long time. Then I realised that I couldn't go on thinking about him, and dwelling over our relationship, it was over and it was over for a reason. I began to enjoy myself more and soon found someone new, it was only a casual thing, and we weren't together very long (difficult circumstances- we were both leaving the country) but meeting him finally put a stop to me thinking about my ex all the time, and I realised that now we'd broken up I was finally free to meet other people and have other wonderful relationships. Sure sometimes I look back and think, god I really miss him, and I can't think about his new girlfriend without feeling just a teensie bit jealous, but deep down I realise that things are better now.
So, essentially my advice to you, is to try and remind yourself of why you broke up, why you're not with him anymore, and that it makes a lot more sense for you to be apart now, because after all he did hurt you and you did break up for a reason. Try meeting someone new, or just talking to new guys, develop a new crush, even if it doesn't lead to a proper relationship it will still make you feel good about yourself and will help you forget about your ex.