What sort of attitude do you generally display? Do you often indulge in public self-loathing, such as posting Facebook status updates that reflect depression or dissatisfaction with yourself, or talking negatively about your life?
I only mention that because of this: "I'm really feeling despair, seeing people all around me coupling up, and I'm tired of missing out on such a fundamental part of life. I'm tryin as hard as I can but I feel I'm trying to surmount a sheer cliff...everyone else has ropes and I've got nothing."
I don't mean to imply anything and I certainly don't mean this to be offensive, but sometimes, things you don't even realize are having an effect are the deciding factor.
I have a friend who is constantly whining and complaining on Facebook and via texts that nothing in his life goes right (when in reality, he's pretty well off, successful in his passion as a comic artist, even is in the process of publishing his own series.) and he complains that he's single, and has asked if I knew anyone I could set him up with.. I wouldn't torment anyone I know with that sort of person, even though other then that, he's a great guy, and I've tried to help him get over it, which he rejects in the same breath he's asking for advice, and it does keep him from meeting interested ladies on his own; nobody wants to be with someone THAT negative. It's depressing.