What is the ruling on a married man with children marrying a second wife through his friend as an agent, and is he sinful due to his first wife's jealousy over polygyny? And is the first wife entitled to demand her rights and her mahr if she seeks divorce because of polygyny?

It is permissible for a man to marry more than one wife, provided he acts justly between them, even if they are in different countries. He should divide his time among them as much as possible. There is no sin on the husband if his wife falls ill due to her sadness over his marriage to another. If the wife requests a divorce because he married another, and he agrees, she has the rights of a divorced woman. However, she cannot compel him to divorce her merely because of his second marriage, unless she stipulated in the marriage contract that he would not marry another, in which case she would then have the right to annul the marriage.