All the texts you sent just proved you are beta to the girl.
Look, if she's not into you, that means you're not her type at the moment. Who cares? Don't you have a type?
I suggest you decide whether or not you still want to be friends with that guy. If yes, sincerely apologize to him TO HIS FACE, NOT THROUGH TEXT MESSAGE, and say that you've been stressed out and an emotional wreck recently or some shit. If you don't want to be friends or can't deal with being friends with him, just apologize to him for being a dick, again face-to-face, and move on. Just throw him a casual "my bad for flipping out" next time you see him. It's solely your problem that you feel jealous and beta.
Either way, they both can date whoever they want without consulting you, in the situation as it is. Had you been actually dating her, then she would have been off limits to him.
By the way, It sounds like you were assuming she didn't like you, which you never asked her, but instead decided for her. But I'll trust your judgment. So let's say she actually wasn't into you, which again you decided for her, then why say anything about liking her? Especially way after the fact. You should have just flirted for a while, asked her out, and get to either a yes or a no. And a no is a not right now.
Try to make more friends, and start asking girls you like out to dinner.
"Hey do you like Thai food? I know a place. We should go, just you and me?"
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