Pauline, it's basic physics. If you read the books, David points out that exercise only helps if you deliberately go hungry, otherwise, working out makes you hungry and you eat more to compensate. But, I lost 18 kg in just over 2 months, and 10 in the first month, and I did no exercise. All I did was stop eating sugar, and eat a whole lot less as I was full. But, I'm not going to tell you that will work for you, or your husband, people can have different medical issues or other reasons that their appetite control doesn't function in the same way. However, if you want to focus on weight loss, you need to eat less. Not eating sugar helps because it SHOULD help you to be full on less, and because sugar goes right to fat, but whatever the details of how you're feeling in regards to appetite, etc, the physics is straightforward. If you REALLY want to lose weight, eat less. If you can't do it by feeling full, then do it by measuring out meals and not snacking.
Remember, before sugar was widely available and in all foods, there were still fat people. Not eating sugar is not the whole answer for everyone. But I do believe it's healthier for every person, regardless of what you end up weighing.