Is it possible he is simply more of the "home body" type, while you are more of the "out-doorsy or get-up-and-go" type? My husband and I have that issue, but in reverse. I am the home body. He wants to be out and doing things. We have had to learn sometimes staying home and doing things like watching movies together (not tv movies but bought or rented movies) or play games together, and other times take time to go for a walk or to the park or beach, or go window shopping. Sometimes I go shopping with him, other times I stay home and he understands I need to feel "safe" in my "comfort zone", and doesn't bother me about it. There are also times when he wants to go off by himself and I understand that's him wanting to feel "safe" in his "comfort zone". Just because you are married, doesn't mean you need to spend all your time together - even when it comes to relaxation time. It took us a long time to learn that. We went through a divorce and remarried for it to sink in
I hope it doesn't end up like that for you.

*hugs*