Im new here :) Looking for serious answers to my confusion?

Is it just me or is something strange here? MY live-in BF of 3 years seems to have a low libido, we are intimate at least once a week....when I come around to initiate he claims to be tired...he was tired all weekend and again last night even though he was home all day! He has a stressful job but no mre than mine! I have talked to him about it and he always get irritable and says he doesnt want to talk about it because he is tired nothing more. I explain to him that he needs to meet me half way here. I will respect him when he is tired but ALL the time, same excuse is odd and a bit selfish because when he is in the mood and comees around I dont deny him, I told him I feel rejected, no one wants to feel that!!!Especially from a MAN that claims to love you with all his heart....allegedly. I have voiced my feelings and frankly I feel completely ignored....he is loving and caring and all that good stuff but intimately he seems distant....any advice is appreciated, serious answers pls. P.S> I am not overweight ugly or smelly so pls dont ask silly things :) Thank you