Been there, done that, got the t-shirt. It was a LONG time ago. I found that the best way to "move on" was to set some new goals for myself. In my case, they were to start saving and shopping for a house, to find a new circle of friends (my social circle was pretty small and kind of dead-end), decide whether I wanted a new job, etc. (Your goals may vary!) I really did write down my list of goals, and I forced myself to make progress on them regularly. Anyway, it helped a lot, especially finding a new group of people to hang out with. I stopped dwelling on the past and started having a good time again. I didn't even seriously date anyone for a couple of years, which might have been a good thing.

