Is it permissible to pay off accumulated debt from the monthly charity amount designated for the needy?

A husband paying off his wife's debt is a righteous act for which he will be rewarded. It does not cut off anyone's provision. He is permitted to do so and then return to his customary charitable giving. Indeed, his charity to his wife is more meritorious than his charity to a stranger, due to the encouragement received regarding showing kindness to wives, maintaining good companionship with them, and treating them with honor.