Hubby is excessively hairy but does not want to shave. What causes this?

Genetics. Except for a handful of unusual conditions (persistent lanugo, porphyria cutanea tarda), the amount of body hair that a man gets is determined by genetics; hairier men tend to become bald sooner. I'm glad for his sake that he likes his genetic heritage, and since this won't change, perhaps you can pretend to like it as well. Some stars such as alec baldwin (photo) also embraced the hairy look.