How to nicely say no...?

My boyfriend and I live together and he wants to have sex every single day, and honestly some days I'm so exhusted from work that I dont want to do anything. But he feels like if we dont do it everyday that I dont liek doing it with him and that I'm a rock in bed. And when I tell him I dont want to its like his feelings get hurt. Is therr anyway I can talk to him about it without hurting his feelings.. Or to try and get him to understand..?