My husband is not diabetic, and he also does all the cooking for the main evening meal, which we sit down and eat together. Breakfasts and lunches we each make our own but still eat lunches together. It has always been this way, so no changes needed other than evening meals.
We don't mix foods when cooking, the meat is cooked separately, the veg are cooked separately, the potatoes are cooked separately. This way he can have exactly what he wants and so can I. It has never been a problem for us, although I do worry a little about him since he saw how well I did on higher animal fats that he followed suit but still eats a lot of carbs.