Lost his sex drive

Girls! I need your help! 
I've recently started seeing this guy, we've been seeing each other for over a month and we still haven't slept together.. I'm not usually the kind of girl that needs to have sex straight away either but it's getting to the point where I'm wondering what's going on. I talked to him about it the other day and he said he just hasn't felt like having sex recently and he hadn't been masturbaiting either, he works a lot and is under quite abit of stress but I'm just wondering if anyone knows if this is the reason he hasn't had any sex drive?