I don't know what to do anymore

So, I thought I'd maybe ask someone for advice here so let me just start:I am gay and I love my best friend who happens to be straight, yet I doubt it that he is straight. I doubt it because when I'm with him and some other friends, he kind of "humilates" me, you can compare it a tiny bit to bullying, however, when I am alone with him he often leans towards me and looks at me, when I look him into his eyes he suddenly looks away. Another example: Once I was playing CS:GO with him and a few other friends. Because I was one of the worst ones, he always kept pointing out that I have no skill and that buying the game was a waste of money for me and such stuff. However when the other friends had to leave and I was alone with my friend, he almost instantly started acting nice as fuck, he was constantly giving me tips and advices and he kept saying that I am not bad at the game, I just need a little bit of exercise.Anyways, today while being with some other friends yet again, I leaned in a little bit to close to the friend that I love and he literally said out loud (damn, he was almost loud enough that you can say that he shouted) "Dude, stop acting so fucking gay" and then he did something really fucking unforgivable: He actually showed my private messages with him where I came out as gay to him, where I admitted that I love him and some other personal stuff...Yet I still love him, he is just so cute and I absolutely love his personality (however I won't forgive him yet for leaking some of my really personal data), and at that point I don't know what to do anymore.. Is there a way how I might find out that he is gay or at least bisexual? Please give me some advice ;_;(Also, I forgive for any spelling and grammar mistakes since English isn't my native language)