You need an account like Starling or Monzo that tracks all transactions live and no overdraft facility so they will be refused if there is no money in the account.
But you also need to check that the money you have is enough for what you need. Are you running out of money because there isn't enough of it, or is it because you are over spending on unnecessary things - if you have bought lots of things for DCs that they have grown out of or no longer play with, is there anything you can sell online or at a car boot sale?
I am getting better at managing the money I have but something always seems to crop up like a car bill or new glasses needed or the washing machine beaks. It's things like that I have trouble budgeting for but they happen
It's good that you've recognised that these things happen, but are you putting the money away for when they do? You need to separate money out for this sort of thing and only spend on discretionary spends for you after stuff like this has been accounted for.
But also is your money fairly shared out or are you falling into the often common trap where the DHs money is for him to spend on himself but the DW ends up spending all her money on the DCs which leaves little or nothing that's just for her?
Maybe separate DC money from your money and put essential DC clothes and days out etc with essential travel and food money and then separate adult spends afterwards - both you and DH should end up with the same amount of money to spend on yourself, even if you earn different amounts.
Put all income into one account and pay all family bills out of this account.
Save some from the joint account for annual and irregular expenses like insurance, Christmas, holidays, broken cars, pets and washing machines.
Put some money in an account for petrol, food, DC expenses.
Split what's left 50/50 between you and DH for own discretionary spending.