I think you’ve set this girl up as the embodiment of everything you want to attain. She is not actually that magical, but hindsight is cloudy and weird and you look at losing her as the loss of something cool and awesome and great. Now, I know what it’s like to regret breaking up with someone. But what happens over time, if you allow it, is that you start to be interested in other people and to realize the negative things about that relationship. I’d make a list of the not-good things about the relationship and tack it to the inside of your closet door. Read it daily as necessary.