Quit "rewarding yourself" with food. You don't need a candy bar to clean anything. You also don't want to teach your kids this no-no.
Make a plan to get the whole family healthy. Just because junk food doesn't show up on the scale for the kids/husband, doesn't mean it is okay. You want to teach them good nutrition to last them a lifetime. Teach them what a proper portion is and stick to it.
As for sweets/snacks, I told my daughter, just because you can get away with it now does not make it okay. My kids only get one sweet treat a day and it is typically after eating a healthy dinner. I like to keep that sweet treat 150 calories or less so your typical pies and cakes do not fit into that plan. Regular size candybars do not either so if we have a full size Snickers it will be splt between two nights.
As far as exercise, you think walking sounds boring but I'm sure if you got back into it, it would become very addictive. It is just a matter of getting started and sticking with it until it is something you WANT to do. Not because you have to do it.
I'm not sure how old your kids are but get them involved as well. Maybe walk at a track so that everyone can walk at their own pace and are somewhat 'contained'.
Get your husband on board with not bringing home any more goodies. You do the same when you do the grocery shopping. If it's not in the house you can't eat it.
HTH