Gaining feelings for my best friend..

I'm starting to gain feelings for my best friend. Only I've never met him in person, and he's my ex boyfriends best friend. I don't know what to do, I don't know if I have a chance with him. And I don't know how to act apon these feelings. Any advice? He's really sweet and he's always there for me, even stays up until 5am to make sure I'm okay (he's 3 hours ahead of me and 3000 miles away from me). I'm confused and nervous. But I cant stop thinking about him. Just talking to him or even just thinking about him puts a smile on my face. Help?