Is it permissible for a husband to release his wife from her promise to move in with the second wife, and is the first wife's consent to the unnecessary second marriage considered a mistake, and is it better to remain in the current home or move to the husband's country in the event of his second marriage?

May Allah reward you for your good character with your husband. You should not be hasty in uttering a covenant with Allah, for your asking your husband to exempt you from the agreement is a retraction and a breach of the covenant. Scholars have differed regarding the ruling on one who says, "I covenant with Allah" and then violates it. Some have considered it like an oath, requiring expiation, while others have not considered it an oath, thus requiring no expiation. The more cautious approach is for you to perform the expiation for an oath. Your agreement to your husband marrying another is not a mistake. As for your moving to live with the other wife in the same house, if you are content and do not fear mischief, then it is preferable. Otherwise, it is better for your home to be separate to avoid jealousy and mischief. A man is not permitted to house both of his wives in one dwelling without their consent due to the harm that causes disputes.