He has loaned something of mine (not valuable or rare), and given how bloody possessive he is about his stuff, I'm annoyed 
If he'd mentioned that X had asked if they could borrow it, or he was thinking of offering it to them to borrow, I'd have said fine; it's the fact he's just loaned it and not told me.
I've told him I'll loan out something of his and see how he likes it.