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A lot of people have said a lot of insightful things in these letters. Yes you are pretentious. Yes, it is normal to be confused and shaken so soon after a breakup - if at all you ever cared for the one who moved out, which I believe you did, etc etc.
However, the only "problem" here is how YOU seem to go about relationships. You can't decide whether want someone whom you love for chemistry, or for what they're promising you (cause you might score 100% for both. People tend to be imperfect like that.) You left your "soul mate" because his ambitions changed and you no longer approved. It's not "wrong", but it doesn't much sound like the actions of a "soul mate" - at least not at an age where people are still "growing up" and so likely to go through such changes. The 2nd guy sounds much the same. So, before you start up with another bf (whomever that may be) you need to figure out what exactly it is you need. Are you willing to support a man as he goes through changes? If not, date older or stay single. Or, prepare to break up if/when they do change/grow. What if YOU go through changes?
Realize that what you have done, 2 times over, is leave a man who has wondered off his path. Not saying this is wrong. Maybe it's right for you. You have to have your needs fulfilled, after all. I'm just saying to take some time, realize what your needs, priorities actually are in a relationship. Then you won't be so confused when you leave someone because they're not doing what you want, then want them back when they are.
Whether or not you are "highly intelligent", what you are not if self-aware. Learning self-awareness would go a long way towards knowing what you need to be fulfilled. At 25, it is not unnatural to still be developing your relationship style, figuring out what you need, etc. It's ok. I didn't figure it out until I was almost 30 (like many folks these days). But figure it out you must in order to find your happiness in a relationship.
Try staying single for a while and learning to poke around your own faults. It will make you less confused about why and how other men aren't making you happy and complete when theirs become apparent.