What's the problem?

So me and my boyfriend have been together for 4 years & we had sex like EVERYDAY!! For a year straight at least, we still continue to have sex but I'm just never in the mood anymore .. We both took each other virgenity , he is still having a higher sex drive then me . I love him a lot but I really don't know what to do anymore . Help!? I try to talk to him about it but it seems like he gets upset and thinks I'm going to hurt him ...