Oh boy Phoenix...
I think all of us have been in this capacity in one way or the other, and I know how troubling this can be.
Truth is your friend is probably very confused at the moment, independently of where he's sitting on the sexual spectrum. I hate to say it but you cannot tell where he stands at this moment, it's gonna take time for him to clear his mind.
I'd give him his space right now - however it's tricky because he's your best friend. Eventually I think things will go back to the way they were, and I agree, having a friend is much better than a lover.
When he'll be ready I think he'll come to you and you'll have to respect his decision. But in the meantime I suggest you train yourself to let go of your feelings for him, no matter how deep they are. Let go of your anger or remorse. What has happened has happened and it's up to him to decide where he stands. He owes you a response, that much is certain.
There's also the option of sending him an e-mail, and let him respond to it. The best way to go on about this is logic and reason. It makes you occupy the superior ground. Tell him how this affected you. Tell him what about his behavior is making things unfair and that you'd want his friendship back more than anything, and that you'll accept wherever he stands as long as he respects you and accepts that what has happened has happened. There's no denying it. However it doesn't make him bi or gay instantly, and that you're willing to accept that.
Be prepared for the worse too.
Like I said, I think someone who's willing to experiment like your friend must be able to face the consequences of their actions and not run from them. I can tell you if he turns on you then you'll know he's always been a cowardly person to begin with.
My friend and I did some stuff together a while back, and he got freaked out. My situation is basically the same as yours. We progressively started hanging out again over a few months, and when I felt the time was right I brought the topic up. He seemed more willing and open this time and he told me he didn't know how it ended up happening, but
it just did. He had time to reflect on it and said he was pretty sure he was straight, but he apologized for what he had done to me, saying there were no words that could express how sorry he was for putting me through hell. He said for what it's worth, he considered me one of his best friends and he'd do anything for me, and that I've at least made him a more open-minded person and he'd always be there for me from now on.
So you'll see I have a feeling things will end up okay once the dust is settled down. Good luck dude
