I write this post as an average guy who somehow managed to overcome a lack of confidence and self esteem, not a lothario who holds the secret key to seducing women. In fact, I think belief in the latter might be one of your problems. Your long, detailed and analytical post is something of a blast from my own past. In short, you're over-analysing everything. It doesn't matter whether you're short, tall, fat or thin, attractive or rather average. Whilst extremely attractive people might get a lot of attention, long term relationships (I believe this is what you're looking for) are just that because people find a kindred spirit, someone who will remain their friend and companion through rain and shine. When two such people meet (and it is a rare occurrence) superficial factors- whether they're in a relationship or not, exes and physical appearances- account for little.
When I was permanently single, I agonisingly overanalysed every non-male relationship that I had. Wondered if somewhere there could be the faintest trace of romance. This got me nowhere and the more I intellectualised the closer to the dreaded friend zone I moved! Now I think about it, I probably passed up a few opportunities to form meaningful relationships simply because I was paralysed through my lack of confidence and unwilling to act due to an irrational fear of rejection. If you like someone, then ask them out. The absolute worst that can happen is that they say "no" in the form of a jumbled and slightly confused excuse. After, you pick yourself up and move on. It is a bit hurtful and humiliating, but what would life be if it didn't have its share of disappointment? At any rate, you massively increase your chances of finding a girlfriend by asking someone out rather than sitting on your gluteus maximus and doing nothing!
One thing I can potentially identify in your post, is that you perhaps lack female acquaintances in your social circles. This can be problematic. The less people you meet, the less likely it is that you'll find a partner. Perhaps you should sit down and consider your interests. There are always volunteer and hobbyist groups that you can participate in. These will provide a forum through which you can meet like-minded people. Whilst I'm something of a traditionalist myself, internet dating is also an option too. There is absolutely no shame in it. The time constraints of the modern world mean that it is increasingly where people meet their longterm partners. Sites such as OkCupid offer a place for you to meet likeminded people, and because it is a dating site the arduous process of turning an acquaintance into a friend and them asking them out for a date is cut.
As I've said before you're far too analytical and adopt an unhelpfully methodical approach to everything. This idea that you'll meet someone, hang out, go on a date, kiss under a starlit sky and begin a relationship is extremely idealistic and detached from reality. Real relationships aren't so clear cut. There's no knowing how you'll end up together. Expand your horizons, seek out new opportunities and constantly meet people. After a while, somewhere along the road you'll meet "the one". Although these words aren't particularly comforting or helpful in the short term you just need to hang on in there, quietly confident that you will eventually meet someone. If you convince yourself of this, you likely will.