Alter-Ego???

Something recently caught my attention. For the past year and a half or so people that I meet or am acquainted with believe that I am married and are surprised when they find out that I am not. This slightly baffles me because I am not sure what I do that gives off a 'married' vibe. Maybe this is the root of all my lack of dating. I asked some friends why people may think that way and they say it's because I seem wise for my age. That makes me laugh but I am still confused what I do exactly to exude the married persona.