Is my boyfriend still doing drugs?

Em

He was doing coke before we got serious. After a night of me and his high roommate getting in to it he decided he didn’t want to end up like him and promised me he wasn’t going to do it anymore. Well whenever we stay at his house and it takes me some time to get there after work there are signs (at least to me, I think they are) of him still getting high. I’ve asked him twice about it already and he swears that he would let me know if he decided he wanted to do it again. But that he hasn’t since he told me he was done. He told me how much he loves me and that he doesn’t want to jeopardize losing me over that. But as I’m sitting here at 2 am while he’s finally taking a shower and finally getting ready for bed, I’m uncertain still. I don’t know if I’m over thinking it and waiting for him to screw up or if I’m actually aware of what’s going on. Help!!!