Is it possible for men to go through a stage when they don't want to have sex?

I have been married for 16 years and until recently never had problems with this area. I am looking for a male perspective. My husband works alot and has a back injury that has fired up again. His sex drive is gone. Most people say " no man ever goes without sex" That answer is too general for me. Always and Never is not a fair statement. Any thoughts....