Put the spoon down, and the lid back on the Nutella!!! LOL, I have been in this situation, and truly still am. My hubby can eat whatever, whenever, and is almost as thin as when he was a teenager. He would still love for me to cook the way I did when we first got married.
First of all, you are doing this for YOU, which in turn will give you more energy and vitality to be able to give back to your family, so in the end they are benefitting as well. Don't ever feel bad about making healthier choices for yourself. And you are being an excellent role model, and it may take time, but that will rub off on them.
Here is an article that might be helpful: www.sparkpeople.com/resource/motivation_ar