Ahhh kids. It may sound harsh, but I think you're both in a fantasy world. Fifteen is far too young to be in an internet relationship. Even if he is who he says he is. (Which is suspect if it all needs to be 'hush hush'.) Teenagers are needy. As such, the internet dating thing might be fun to pass a boring few hours but in the long term I'd bet dollars to donuts it just doesn't work out.

Perhaps ten - fifteen years from now when you've dealt with the perils of dating, and have the maturity and experience enough to recognize somebody taking you for a ride it could work. But for now, you're too young to deal with this 'boys' life issues. Tell him to see a psychologist and keep your dating local.