Having a lot of trouble forgetting my ex after 2 years!

Around March 2014 i hooked up with this girl, she was my second girlfriend. Only a week after we met she broke up with her boyfriend and hooked up with me, it happened insanely fast and we had more things in common than anyone we ever knew. The only problem was that we live 30 kilometers (around 18 miles) away from each other, so for the short 3 weeks we were together, we only saw in person once a week, plus the night we hooked up, so 4 times, the fact that none of us could drive was also a thing. Although, the 10 000 messages on facebook and at least 90 hours on skype make up from that. And i promise you, those three weeks were most fun i EVER had. Then suddenly, literally over night, she just STOPS messaging me, I try to get an answer, nothing, so I put my phone down, go to my friends house and have fun, thinking she is probably doing something important, she spent a lot of time in the hospital during that last week, etc. And out of nowhere, around 9 PM, our mutual friend calls me and asks me: "Hey, you know Sarah broke up with you?" (I'll just call he Sarah), I had no idea what he was talking about, nothing led to this, i checked our messages a couple of times after, nothing, she was cheerful all the time, saying she loves me etc, she was also quite jealous when it came to me being friends with other girls, leading me to think she cared about me more than i had thought. Then, after I say no to my friend, he continues: "Yeah, she met some other guy last night and ended up with him at the end". At this point i hear a couple of people whispering in the background on my friend's side of the call and say: "She's listening to us right now, isn't she?", my friend confirms. After remembering what happened to the last guy she broke up with (he got made fun of a LOT for never being able to get over her) i decide to say the safest thing i can, i say: "I don't care" and hang up... That night, i get drunk a.f. and barely walk back home. The next morning i wake up to see that i sent her a message, quite a long one too, with all kinds of dumb bullshit, most words don't even make sense, so I apologize to her, to what she reacts like i'm lying I was drunk and didn't know what i was writing. Anyway, a couple of weeks pass and we don't talk, but then she messages me again, I was about to move to her city because of school and she wanted to know what i'm going to do about the apartment. I talk to her casually, not bringing up ANYTHING that happened and we finish the conversation, not talking for the next 6-7 months. Even then, the talks were short and dull. We remained friends on facebook and she still likes my pictures, leading me to think she never got mad at me for saying the stupid 'I don't care', also, i never moved to that place. My point is, even after two years, during which i followed the only advice people gave me (try to forget about her and date other girls), I managed to ignore her, but never forget her, i tried dating a couple of girls, most of those relationships lasted either a couple of days, or ended on the date, mostly by my choice. I can't stop comparing other girls to her and said to myself i won't try to get into a relationship with any girl unless she is equal or better than Sarah. After meeting (meeting, not dating) dozens of girls, i still can't find one like that, got very close a couple of months ago, but that ended badly. To be honest, i don't know what i'm asking of you guys, any sort of thoughts on this would be helpful, thanks in advance and sorry for the long post...

Given only 3 short weeks, and considering the initial few weeks/months are when one puts ones BEST foot forward, she didn't half act-up super-badly, don't you think? What did she think that was - foreplay? ;-p Just because you hooked up so quickly with that ex, doesn't automatically follow that any subsequent relationship will likewise happen that instantly, PARTICULARLY if that relationship was 50% 'sent' to highlight whatever relationship inconducives and weaknesses you might possess but which you since haven't yet sat and examined in order to work out what those self-working-on demands are. Once you've done your 'homework', then you'll be ready to take the next exam and be awarded your diploma trophy. Sounds new-age bonkers - isn't. That's how it works. So - including initial judgement in terms of choice (asking out her specifically) to the final curtain, what do you suspect are the things you did wrong that you could have done better? However, saying that, you will have made SOME mental progress in two whole years. So I imagine if you contacted this ex, you'd find her not nearly as attractive to who you are now as you did at the time and have believed she's remained as ever since. I don't think you want back with her, anyway. I think you just want closure. I mean, as a Facebook user, you do KNOW, don't you, that people tend to hang on to "friends" for number and 'public embarrassment' avoidance purposes (re those that might notice the sudden decline in number of friends or that specific, new omission of one)?