All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
We have already issued Fataawa 92004 and 85361 clarifying that a husband is Islamically obliged to spend on his wife and children. Hence, if the situation is as you mentioned in the question that your husband is not fulfilling this obligation, then he is negligent and wrong. Therefore, he should be advised in a soft and gentle manner and reminded of the saying of the Prophet : “It is enough a sin for a person not to provide means of sustenance to those whom he is obliged to support.” [Ahmad and Abu Daawood]
Besides, if you need to appoint some righteous people to reconcile between you and him, then you should do so. If reconciliation takes place, then praise be to Allaah. However, if he insists on refusing to spend on you and on your son, and he refuses to fulfill his responsibilities, then you should take your case to an Islamic court, if any, or to the institutions that are specialized in solving the issues of the Muslims, so that it will oblige him to spend on you or to repel the harm off you by divorcing you from him or getting you Khul’ from him.
Finally, it should be noted that it is permissible for the wife to ask her husband to reimburse her for spending on his children if she did so with the intention to take it back. Also, your husband is not exempted from spending on you; rather, this remains a debt on his liability. For more benefit, please refer to Fatwa 85012.
Allaah Knows best.