Unfortunately, it's not something you can make happen just because you'd like to be over the ex. I suggest keeping active with your most fun and upbeat friends, trying new activities you've always wanted to try, and going to new places you didn't go with the ex, so you won't be thinking about him or her when you are out to dinner or wherever else you used to go together. The other important factor here is time. It's just going to take some time...