If a legal alien couple get divorced can the husband stop the wife from leaving the USA with the children?

Yes, If they got their divorce in the U.S., their divorce decree should state certain rules each must follow concerning the children. For example; whom ever has physical custody cannot move within a 35 mile radios from the father Or mother, another example; Cannot leave the state without the other parents consent. A letter should be sent to the parent certified containing all information ie; where they are going, phone numbers address etc.. If the father does not have joint custody or vistatation or these specifics are not in the divorce or vistation papers, then he should run not walk RUN to court and adjust his divorce decree accordily. I know this info. because my Ex-boyfriend divorced his wife(whom only just received her working papers)and I am sure his wife would have ran to Mexico if I did not go through his papers with a fine tooth comb. He can read minimal English and even with a high paid Lawyer there still were mistakes. Her lawyer would slip items in the papers (at her reques) but we picked them out. If he has questions seek a lawyer. Good luck and God Bless!