Will the husband be sinful if he does not provide his second wife with things she does not need, and will he be sinful if he divorces her due to her infertility and her overwhelming jealousy of his children, knowing that he fears God's blessings upon him will change if he divorces her?

Justice between wives in terms of expenditure (nafaqa) and overnight stay (mabit) is obligatory. The children's expenditure is separate from the mother's expenditure. Therefore, the second wife is not entitled to demand the expenditure of the first wife and her children. Rather, she is only entitled to demand expenditure similar to that of the first wife. The wife should be content with what Allah has apportioned. There is no sin upon the husband if he divorces the aforementioned wife, but it is advised to keep her and treat her kindly as long as he is able to do so.