Is it weird.....

Is it weird that my husband won't have sex with me?? Not meaning to get personal but we have sex two to three times a week...these last two weeks we has barely even touched me..when I try for it he comes up with some lame excuse like "I can't the dog is laying on me" or "let's just go to sleep"...not sure what is going on but this is unlike him...should I be worried?