Is it normal i get annoyed when my brother does this?

I'm very territorial when it comes to my things and don't like people touching my things my brother who is 3 years older than me I'm 21 always takes my stuff without asking like my usb cable, my cds and I always hide these. This morning he took my earphones without asking me we've had numerous arguments about him taking my earphones but he always says "relax they're just earphones" of course I know they're just earphones but they're mine. He even goes on to say "I pay cable, I gave you half of the money to buy your phone I do plenty of things for you you should not even be confronting me about silly earphones" Am I wrong for being furious with him for this? At the end of the day its not about the earphones but about respect. How should I approach the situation? I'm tired of hiding everything it's not like he can't afford his own stuff he can but he's just like that.