Most Helpful Guy
Well, it's only been 3 months, not usually a long time for a 36 year old. Sometimes guys like that clam up in new relationships. Give him some more time and see if he opens up a little more. A little progress is still progress. Just be patient.
Most Helpful Girl
He's probably afraid he'll lose you so you should let it be known that you're with him to stay. My guess is that since he won't introduce you to anyone he might not want to get judged because of age difference