What is the ruling of Islamic law regarding the actions of a husband who engaged in a relationship with another woman, and what should the wife do to preserve her family according to Islamic law?

The questioner should advise her husband and warn him, fearing Allah, against any forbidden relationship. If the husband repents, the wife must accept his repentance and not reproach him for his sin. She should be a good and beautiful wife to him. The husband must sever his relationship with the other woman and show aversion towards her. As for the reasons for preserving the family, its foundation lies in fearing Allah, fulfilling His commands, and refraining from His prohibitions. Allah has guaranteed a good life in this world and the Hereafter for the believers, and Allah defends those who believe.