I may be falling for an old friend

I have a crush on my friend of about 5-6 years. We've always had a slight sexual tension but never went into dating aspects. Now we have a "flirtationship" which is actually more like a fake relationship. We get "fake" jealous and call each other pet names through text. But I can't tell if we're actually developing something or if we're just playing a game. I feel like it shouldn't be that hard to tell the difference but things change so much. How can I find out what's really going on without being too blunt or harming the friendship, or relationship, or whatever it is.

If it's been 5-6 years, then you should be able to discuss this 'issue' with your friend without harming your friendship. Ask yourself why you never actually dated.

I'm currently away at school so it's hard to get as much face to face contact with him.