Good luck with this. Long distance relationships are fairly tough as it is, but to add the fact that the other individual doesn't think he's gay adds a whole different level to the problem. I think for your own peace of mind you'll need to clarify that issue first and find out what his true feelings are for you. Then, if he's not gay, you'll have to decide if you're willing to have a platonic relationship/friendship with him. It won't be easy either way, so I wish you the best.