You may have symptoms of what is called a personality disorder. You would appear be be above average in intelligence, but at 31 years of age, you haven't had much success forming or maintaining intimate relationships. This is one key point---though you would like to have such relationships, they don't seem to pan out or really last. For me, this is usually an important hint that the person may have a personality disorder or a mixed disorder. Therefore, I concur with the path you suggested in your first post e.g., you have read about these already to some degree. Therefore, I'm sure you've discovered on your own that there are about 10 formal ones and 4-5 others under research consideration). But what you may not know about personality disorders is that the formal designations of individual personality disorders is quite a 'mess' in psychiatry. This assertion is supported by lots of indirect evidence. For example, it is well known that few people with an apparent personality disorder actually meet all of the diagnostic criteria for any one disorder. They show a sort of 'mixed' disorder---1-2 features from several different' formal disorders. Alternatively, they show either very mild features of one or more disorders or don't fully meet the diagnostic criteria for any one disorder. So such personality problems are usually classified under something called Personality Disorder NOS or Not Otherwise Specified.
My hunch is that you may have one of these mixed types that could involve 1-2 mild features of several disorders---probably not enough for a formal disorder designation, but enough to cause you some difficulty in your social relationships; Consistent with what you have suspected, I would focus a formal evaluation with you on a number of personality disorders, with the hypothesis that you have a mixed type e.g., avoidant, schizoid, schizotypal personalty disorders. You mentioned Aspergers, and interestingly, this came to mind for me as well; but given your several posts to me, I doubt you fit criteria for Aspergers very well.
I think you are bright enough to benefit more than most people from psychotherapy, either individual or particularly group psychotherapy. I think you would find social feedback, and being able to provide input into other peoples' problems within a group psychotherapy setting to be quite interesting and helpful to you.
Let me pause here and solicit your feedback. I want to assess whether I am addressing your question adequately.