Well there's a reason like everyones saying, that you shouldn't go back to your ex. My favorite quote, says: what it means to have an ex, it's an EXapmle of what you shouldn't have again in the future xD. So why would you wanna go back to him? You broke up with him for some reason, or he broke up with you for a reason.
I wouldn't go back to him either way, even if I still had feelings for 'em. :)
I hate to take the other side, but the whole 'an ex is an ex for reason' answer has been disproved by a family member, a best friend, and my butcher. Nothing is impossible and people do change (on their own). But as for your situation - this has less to do with you and more to do with your ex. What's he doing? Has he shown any interest? Or are you just missing him because you felt better with him than you do now? If it's the last one - you have some pain to go thru and some growing-up to do (you're not alone). Bottom-line: You have to be happy by yourself before you get involved with ANYONE else.
If you are in love with your ex but he does not know you need to tell him that, however it is very important to be sure that it is not an obsession but love. You should be sure that he has not moved forward and that he feels the same way about you. http://getbackmyex.com/Still_in_Love_with_Ex.html
Sometimes. You may think you still love an ex. But are you sure it's not just familularity. Someone that you are used to being around. Meeting new people can be scary so it's natural to want to stay in comfort zone but everyone is right it ended for a reason. Meet someone new.