As another male, I can tell you this guy is in all likelihood 100% trouble.

Not just because, as mentioned, he is irrationally and unjustifiably jealous over somebody he's not in a relationship with. Also controlling or manipulative because he will not fold until you admit you've done something wrong.

Lastly, and maybe this is just me, but that stubbornness or narcissism that causes people to be totally incapable of being wrong or to acknowledge misunderstandings and move on absolutely drives me nuts. They always have to be right. Everything is always an attack on them. They always have to be apologized to. They are always trouble.

Maybe I'm reading into it too much but I think if most guys had a female friend they were interested in and she said something like that, they'd use that opportunity to flirt with you rather than fight with you. "Well yee'haw! Let me get my hat and boots and we can mosey on down...". etc.