Is the husband considered sinful if he prevents his first wife from abstaining from attending family occasions due to his marriage to another, especially since she also prevents their children from attending, and he wishes for all members of his family to be present?

Polygyny is a legitimate right for a man and is not considered an injustice to the first wife unless there is a clear bias towards one and neglect of the rights of the other. It is not permissible for the wife to disobey her husband simply because he married another; this is not an insult to her, but rather it is Allah Almighty's law, as stated in the verse: {then marry those that please you of [other] women, two or three or four}. Nor does she have the right to prevent the children from attending events their father wishes, provided they are free from forbidden acts. The wife must fear Allah and obey her husband, for obedience to the husband is among her most obligatory duties. The husband has the right to take the children with him to events against her will, but he does not have the right to force her to attend an event she does not approve of.