Its not cheating if He's on the other side of the world ?

Everyone has their own opinions of what is and isn't cheating, but I think it's all just moral relativism and pretty low to be trying to justify crappy behavior like that, lol. But that's me. You have a few options what you can do here.

You can dump your boyfriend.

You can get over your little crush on this other guy. Quite possibly it's just a meaningless little crush that doesn't mean anything about your relationship as long as you don't act on it.

You can talk to your guy about making your relationship a little more casual. Odds are good he won't like it and it will lead to breaking up down the line (or possibly right when you suggest it), but it's an option. You're under 18 so you're young anyway. No real need to be tied to one guy at your age. You could try telling him that you still care about (or love) him and you want to be together but you feel like the distance is too much of a strain for both of you. That you should BOTH feel free to date casually until he is back, without guilt. If you go this route then you should set up rules in advance for what you will and will not allow. Big one being whether or not sex is ok. Don't want him getting back only to find out he screwed like 10 different girls and thought it was "ok" because you went on a couple dates with some guy.

If you guys are "meant to be" then you'll get back together whatever route you choose. And if not, you'll both probably feel some pain, but you'll also both get by.

Important in your decision, you should ask yourself if you really do still want to be with your guy, and also how you would feel knowing he might be dating other girls over there. With or without your knowledge.

End it with your boyfriend now! DONT CHEAT! even if he is across the world, its not right! If you fee that tempted to be with someone else then your boyfriend now isn't right for you (right now but maybe later)