Is it permissible in Islamic law to supplicate for the heart of a wife who loves someone other than her husband to be turned towards her husband? And what is the appropriate wording for such a supplication?

It is permissible for a Muslim to ask their Lord to make him beloved to his wife and to all other Muslims, due to what Muslim narrated from Abu Hurairah regarding the Prophet's supplication for himself and his mother for love. There is no specific supplication to attract a wife's love, but the matter is open, and one can refer to fatwas regarding permissible means of fostering love between spouses.