Hi Cynthia,
Good for you for reaching out and seeking a solution for what you think could be a hindrance to your happiness in the long run. Hanging onto an ex is very common and the best medicine is time. I happen to be working on an article on this topic so here are my highlights that might help. There are a few main reasons why we hang onto our Ex.

1)We tend to glorify the good and forget the “bad” (bad: what was incompatible)
2) We are afraid of our grief and hanging onto them helps us delay our process (most people fear their feelings!)
3) We feel guilt for the mistakes we made and a part of us fantasizes about getting back together and doing everything right this time.
4) Heart takes time to let go. In my experience, if you really want to let go and move on, it takes about 1-2 years. It doesn’t mean that it will be excruciating the whole time. It all depends on your perspective.
5) We forget that relationships are spiritual assignments. They have their expiration and that is OK. Not all of them are supposed to last a lifetime. It does not mean that the relationship was bad or meaningless. It means that you got what you needed out of it. Now process, extract wisdom, make necessary changes (do your inner work). When you’re ready, the next relationship (next assignment) will show up.

Here is what worked for me:
Make a list of what worked and didn’t work. Be realistic.
Keep a journal and process what comes up.
Delete him from your Facebook (constant FB checking does not help at all!)
Get out and start doing new stuff (volunteer, take a new class, start a book club, etc..)
Give yourself permission to feel your feelings. Don’t resist what comes up but don’t indulge.

Hope this helps. Additionally, I wrote an article posted here on TB about my experience after my break-up that might speak to you:

Why Love Addiction Deprives Us of Love, and How to Let It In

Warmly,
Banu