Wanting sex more than my boyfriend

I don't know if I just want more sex than my boyfriend or he's just really tired. My boyfriend works at least 50 hours a week from 2-midnight monday through Friday so we really only see eachother late when he's off and occasionally on the weekends if I don't work. I'm always in the mood for sex when I see him, we probably have sex twice a week but I could go for twice a day everyday. I can tell he loves me and he treats me well but it's so hard to get him to have sex sometimes. Should I be worried or just accept and understand that he's probably just too tired