Is it permissible to marry another woman while keeping the first wife who is afflicted with sorcery?

There is no objection to marrying another woman if you desire to marry and are capable of fulfilling the conditions of polygyny. In fact, it is preferable out of compassion and loyalty. You can learn about the symptoms of someone afflicted by magic and how to treat them by referring to Fatwas numbered: 40128, 32449, and 71177.