I agree with DNAnon, sounds like he is using with his erratic behaviour and confidence.
I only had to check the pockets of jeans, trousers and jogging bottoms before putting them in the washing machine, to find little plastic packets. Sometimes with coke in and sometimes ones that had been used. Don’t forget to check the tiny pocket in his jeans, it’s the ideal size for a bag.
Even if your boyfriend thinks you are being negative you are only doing it because you care but this will put a stain on your relationship as you are onto him and he is trying to hide the fact.