tink I don't know why you started this thread, tbh, based on the last.
Your DH is the only earner in your marriage, he's labouring under the mistaken impression that you are using your benefits every month to spend on the DCs when you're actually using it to pay off £1,300 of debt. He needs to be able to budget what little money your family has left over after bills etc. He can't do that if he thinks you (plural, a family) are £135 a month better off than you actually are.
Will it be his fault if your DC loses a school jumper, needs to buy a new one from the school, and you can't afford it because he doesn't know he needs to be setting extra cash aside for these kinds of expenditures?
You both came to a mutual agreement that he would pay the bulk of his salary into the joint account for the mortgage, bills and food. You both agreed that he would then use what little he had left for petrol for work, to treat the girls occasionally and to get lunch at work. You both agreed that you would use your benefits for monthly expenses for the DDs.
Your are lying to him. You have run up debt buying things for the girls that they don't need; things that make (by your own admission) a small, cramped house even smaller.
You seem to think that your DH won't find out if you don't tell him. He will. As I said on your other thread, he is going to twig something is up when you keep going to him to get money for things that you both agreed would come out of your benefits. He is going to wonder where £100 a month (that you're paying towards the different credit card debts) is going. He will ask questions.
If you're comfortable lying to him indefinitely (because that's a large amount that will take a while to pay off), then go right ahead. But that's no kind of marriage.