Sex problems

My boyfriend believes sex is important in our realtionship ( ok I agree) we see eachother about 2-3 days a week sometimes more depends on work hours and we have sexual encounters everytime. 
But now and then he says about us not having enough and how he wants me
To be really sexually attracted to him ( i am) but be believes I should want sex with him all the time. I would but I don't see him! Is he not happy with our sex life or?? I don't understand