Long posts are good, how else to explain your situation. You are doing great that's an awesome turnaround in a short period. I too never went through the stages of grief post diagnosis, I spent 6 days in the hospital on diagnosis, and was told I might have heart failure(I didn't), so the fact that it was only diabetes was almost a relief. Like you I decided to just do what I had to do to deal with my new reality.
Perhaps you need to let your wife work through the stages of grief, after all your life has changed irrevocably. I suspect your good attitude will rub off over time. The evening walk could turn into a positive, it's good for everyone, diabetes or not, and its an opportunity to spend time together. Adjusting your diet generally means eliminating problem foods for a T2. Instead of thinking about the foods you cannot eat, you could just as well explore all the wonderful ingredients and recipes you can eat. There are tons of great low carb sites on the web and there are several excellent low carb recipe groups here on TuD. Another great source for recipes here is the Bernstein Group although it's not a recipe group per say there are several great cooks there who share their favorite recipe's from time to time, I've found several favorites there.
Finally, perhaps try to involve her in tuD. This site is full of people who are successfully dealing with diabetes and are leading full and happy lives.