If you are driving without a seatbelt, then this is not that bad, because you only endanger yourself - a fine would be enough, provided that you have no priors.
But if you get pulled over and your child isn't wearing a seatbelt, then it should be fucking game over for you. If you can't keep your kids safe, then your kids should be given to foster parents who can. Put yourself in danger all you want, but don't you dare fuck around when it comes to your kids' safety. Every child deserve to be safe.