We're both 24, have been together for almost 2 years. At first it was pretty casual - he likes to be alone a lot, and I've done my best not to push him in the hope that something more serious would come out of it, which it has. I see him/stay at his house almost every other night now and he's gradually starting to include me in more things. But he still won't introduce me to his family - every time I bring it up he changes the subject or just ignores it. He's close with his parents, and I know that they know about me - but what does that mean if after 2 years he still won't introduce me to them?