Exes bra.need advice ASAP

So I was putting laundry away for my boyfriend and under a bunch of junk stuff he moved earlier in his room was a a bra. Not mine. I didn’t touch it and just left it where it was assuming it’s his exes and I’d say something to him. But he came in and saw it and thought it was nonchalant tucked it away and went to do what he was going to do as he hid it he said he has to clean tomorrow not knowing I saw everything. I want to say something like, you wanna throw that bra away instead of hiding it? Or should I just leave it be?