Been there, done that! I had a husband who wouldn't backpack either. Frankly, I can understand your husband's aversion to hiking--being a mail carrier will do that! I finally started first easy hikes and then backpacking with a group. Then I moved for a new job and started going on my own. In the meantime, I gained weight with each of my 5 pregnancies and still fight the Battle of the Bulge! For the past year I was pretty much immobilized, first due to plantar fasciitis and then by my dog's illness and passing. Now I'm hiking again and this week I will take my first backpack in two years. It will be a bit sad because it will be my first backpack since my dog died, and I'll be taking his ashes up to a beautiful flower-filled meadow on the north side of Oregon's Mt. Hood.

I have never had a bad encounter on the trail so I don't worry too much about protection--your chances of either hostile human or animal encounters are infinitesimally small, maybe 1 % . The real dangers to worry about are falls, hypo- or hyperthermia and, above all, auto accidents driving to and from the trailhead. Secondary to those three in probability might be accidents crossing streams and lightning. By all means take the dog with you, for companionship, but, as suggested, keep him leashed. Also work on getting him, as well as you, into condition before you take more than short trips. That means lots of walking, including day hikes. If your DH is worried about your going alone, take a SPOT or a PLB or Delorme Inreach with you (don't count on getting cell phone reception in the wilderness).

You might want to read the articles on the home page of this site to refresh your knowledge. We also have threads for beginners (again, useful as a refresher), on hiking with animals and all sorts of other backpacking-related topics, with a focus on light weight (lots easier now than it was 20 years ago).

In the meantime, keep walking; take the dog with you and before you know it, you'll both be in shape!