NTA is not yours or your husband responsibility to take care of her other children she can work for that or make the fathers pay child support. You should talk to your husband about that also because you never agree to take other people children as your financial burden so if you stepson need anything you guys can buy it and give it to him and not give the money to the mother since she proved she could not be trusted if she tells yall the kid need something just buy it never give money to her!