If I had to rely on motivation and/or willpower, I'd be sunk more days than not.
A bigger motive force for me is inertia. I'm in my comfortable little rut--kitchen full of plan-friendly food, no cash with which to buy delivery stuff, exercise bike looming over my right shoulder as I type this--and I would actually have to pry myself out of the rut and into another to go off plan. In a way, it almost nullifies the idea of success; can it be truly called "success" if I'm just too lazy to fail?
Maybe you just need to reinforce and deepen your own positive ruts. Motivation won't happen each day, but habits do; I don't need to feel motivated to brush my teeth when I get up, it's just what I've done pretty much since I grew teeth.
Until you get into that groove, though, you can spend time preparing for it. Shop for new, friendlier foods if you haven't already. Are the kids old enough to give you some suggestions on stuff they'd like to do? If so, plan a day around going somewhere they suggest; kids eat that stuff up.
Take some "me time" and give yourself a mani/pedi; you absolutely
cannot eat cheetos when your fingernails are wet (yes, I once tried and yes, I got orange crap in my "Hollywood Scarlet"). Cook like a fiend so you have heaps of good stuff to eat for the next week.
Don't sweat a bad day. Bad days just exist to remind us of how enjoyable the good ones are. And your weight loss? Your weight loss can handle
anything you throw at it, as long as you stay committed to it for the long haul. Even a craptacular binge day is just a little speed bump when you look at the whole landscape.