What are my legitimate and legal rights after my husband secretly married another woman and I requested a divorce?

A man's marriage to a second wife is permissible in Islamic law, and he is not required to seek permission from his first wife. There is no impediment to his marrying a second wife before consummating the marriage with the first. It might be better to delay this, out of consideration for the feelings of the first wife and her family, and he is not required to inform his family. The wife is not permitted to demand a divorce unless there is a legitimate Sharia reason, and a man's marriage to a second wife is not one of these reasons.