I'M NOT GETTING SEX

Ok so me and hubby been together for 6 years married 3 years ...now he has been working the same schedule since and before we met .. we would have sex everyday now it's only 2 or 3 times a month .. I'm soo confused on what can possibly be going on !! I'm 26 he is 35 ... he soooooo sweet to me but he doesn't give me sex hardly anymore ....WHAT YALL THINK?