Sounds pretty rough. You might set a bed time for them or at least a time when they have to be in their rooms getting ready for bed. I don't know how old they are but staying up till 11 for younger kids is probably not the best idea :) If that's not really an option, maybe after dinner you have a family walk time where all of you walk around the block for 15-30 minutes. That will get you all active and spending time together just as you would in front of the tv and will also encourage your kids to live a healthier lifestyle as they are growing up. Most kids get their routines from their parents and if they see you over eating and being a couch potato, they are much more likely to do the same when they're older.
Another alternative is to do things during your normal day. For example, when you go to the bathroom, do 15 wall pushups before you go back to your desk. Every 2 hours while at you're desk, do 10 pushups. When you're at home watching TV with your wife, do 10 jumping jacks during a commercial or run in place for 2 minutes, etc. There are ways to encorporate exercise into your day that doesn't take much time.
If you aren't able to exercise, try watching what you're putting in your mouth. I totally understand that limiting yourself to portioned meals is hard at first, but if you find foods that you like which are low in calories and more filling, then you can eat more of them and not be taking a hugh hit calorie wise. You mentioned you rebel in that way. You aren't really rebelling against anyone but yourself. No one else is going to take your health into consideration and do the work for you.
Take a look at the following article: www.sparkpeople.com/resource/nutrition_art
I read this a few months ago and was shocked to see the difference both visually and when I eat. You can have so much more food if you choose healthy vs choosing a non healthy portion. The healthier options aren't just the same amount of calories, they have less fat, sodium, cholestorol etc and benefit your body as well. You don't have to sacrifice taste either.
To offset hunger I make sure I'm eating quite often, every 2-3 hours. I eat small meals and snacks.
For example, I'll have breakfast at 7, snack at 9:30, lunch at 12, snack at 2:30, dinner at 6 or 7, an sometimes a snack at 9.
I also drink plenty of water, 8-12 cups a day. If you carry a water bottle with you, you'll find that you'll drink the water :) Drinking water offsets hunger when your blood sugar drops and keeps you from running to the vending machine at work to buy candy, chips, or cookies.
Hopefully I've shown you several options that you can try. It all comes down to making choices for the better though. As long as you're battling with yourself about just starting a fitness routine or watching what you eat, things won't improve.
You're out here for a reason and you want things to improve so you can stop feeling guilty and battling with yourself. Make it happen.