Secretly in love

It started with harmless flirting. But after a while, it became more to me. We been friends ever since I can remember. So what change? I don't want to ruin our friendship over these unmasked feelings toward him. In my opinion it would only draw us farther apart. Not closer together. And I don't think I'll be able to handle that. So what am I supposed to do? Hide what I really feel about him inside? I mean, he's my best friend for Christ sake! It's hard hiding things from him. Or at least it was anyways...