Well, I am neither wife nor mom so my schedule is probably different than yours, however I think I understand the questions. For me, it was just a matter of doing it. There is no way I can "make" someone else fit in fitness and health. Goodness knows, I could barely make myself do it. I started working out when I was 30. It took at least 6 weeks for it to become habit and 3 months to get where not working out felt weird. I was vigilant with excersize for about 1 1/2 years then I stopped. When I went back to the gym, it was another 6 weeks of making it my habit. Really just forcing myself to go. I set up a little rewards sytem to get in gear. Sounds silly, but I put a cute Hello Kitty sticker in my date book for every day I worked out. It made me happy.
Now I am doing South Beach as well as working out. I had the extra incentive that I needed to get the carbs and sugars out of my body for health reasons, but I know it will take at least 6 weeks total for this life style to become habit, not just something I am trying. I am learning to squeeze vegatables into every meal. After two weeks of no sugar, organic baby carrots tasted so sweet!
As did almonds. I replaced my nighttime snack with a cup of plain soymilk. Again, with the absence of other sweets, it tasted perfect.
However, the temptation is always there. I like chocolate and don't like to cook, so I always want to run to a convience store for a quick can of soup, but I know that is a slippery sloap for me.
Anyway, sorry, I am getting off the point. How old are your kids? Are they yourg enough that you can work this into a game? Some way to read the nutrition lables and have everyone peice together a meal w/a certain about of fat/carbs/sugars/whatever that you are monitoring? Are there gyms in your neighborhood w/daycare services? Someway that you could work your whole family into the changes would probably work best.
Good luck! I hope I helped a little.