Most meals end up compromises. So today we had lamb stew but the kids had bread and butter with it (they all hate potatoes!) Or we might have bolognese and the kids have spaghetti whereas the adults have courgetti.
Will your children eat things like curry? There's a lot of curry recipes that already use cheap cuts of meat, and you can adapt the ingredients if necessary to reduce the carbs (those bloody onions ) - they could then have rice/naan/etc and you and your husband could have kale (or cauli rice) You could also do veggie curries- Indian or Thai - and portion of some for your children to add potatoes into.
Slow cooker recipes too seem to use a lot of cheaper cuts of meat. Otherwise - egg based meals: tortilla/omlette etc with potatoes of some sort on the side for them?
If you're cooking veggie stuff - you probably know this already - for things like cauli and broccoli, it will be cheaper to use frozen, and this is often fresher than the "fresh" stuff from the supermarket anyway, as there's strict guidelines as to the total time allowed to go from field to freezer: so it can be as little as two hours from picked by the time you stick it in the saucepan.
I make portion of couscous for my kids and flavour it with some concentrates flavour such as Sacla sun dried tomato pesto. You aren't saying how old are your kids but I would say one jar should last for 6 portions. SO yo umay be able to get 2 full servings for all of them.
I tried cheaper Sainsbury's pesto and it just tasted like a concoction of chemicals
Rice in ethnic shops is cheap and serve them with a mild curry you and DH can have with vegetables.