Pretty sure I'm falling for my best friend..

I don't know if the feeling is reciprocated, obviously my thoughts are going to be biased - wishful thinking. I don't know what behaviour crosses the line from best friends to more. Some times we cuddle for hours and it gets touchy feely, we end up holding hands and he rests his hands wherever, like on my thighs. We play fight/tackle but I would think that this is pretty standard? Some times it gets to the point where we are about to kiss one another but neither of us leans forward first.. if you get what i mean.

I want to come out and admit that i like him but how do I do it tactfully? I keep hinting, I say lame things like "I never want to lose you [to another girl]" and he'll say "you won't. when i get a gf, you'll still be in my life" and this makes me re think whether he likes me?

but he's the kind of guy who doesn't believe that a girl can truly like him. He's that shy guy. you know what i mean..