You've been manipulated for years. Conditioned to 'think about the good times' when he's treated you badly and needed to reel you back in.
This is habit. Pre-conditioning. Common upon departure from an abusive relationship. There's nothing unusual about what you're feeling; it's the healthy emotional response to an unhealthy situation. You are having emotions as per your previous experience. That's what healthy people do.
The trick now is to make sure that the future experiences you have are healthy ones, so that you rehabilitate your emotional responses. You need to make sure, in the future, that you are only spending time with people who care about your feelings, support you in doing the things that you want, and support you when things don't go the way you hoped.
The most important person, the very first person, who you need to make sure is doing this stuff for you, and respecting you in this way, is you.
So start now. If a friend came to you and said they were hurting after a break up, would you say 'Why?', or would you be more supportive, offer them things that would comfort them and make them feel that they weren't unusual in having their feelings? Do this for yourself. Don't question your feelings; they are what they are. They are the real you. They are your soul. Respect them; answer their calls for comfort, support, and love. That's what you were constantly looking for from him, and presumably, if you stayed for so long, he sometimes showed signs of giving to you. You need to find ways of giving those things to yourself. You'll feel better then. It's not him you need or want, it's the feelings of potential fulfillment of your needs that you've attached to him. Make them separate from him.
You have to love you, to obliterate your need for him to love you. 