if wife had a love relationship with her cousin and the cousin asked for forgiveness but the wife out of stubbornness is saying we did not do anything or I did not do anything then what should the husband do? There is evidence pointing to them having an affair with text message and pictures but the wife, out of stubbornness, is saying she don't trust the phone or does not know what it is. The husband is worried that she will talk to him in future and wants her to admit, so she doesn't talk to him, what should the husband do?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His Slave and Messenger.

In principle, a Muslim is not sinful unless proven otherwise. It is impermissible to accuse a Muslim of any offense or sin without clear evidence. This is even more emphasized between the spouses, given the sacred bond of matrimony. Marriage is a solemn covenant as described in the Quran. Allaah, The Exalted, says (what means): {And how could you take it while you have gone in unto each other and they have taken from you a solemn covenant?} [Quran 4:21]

For more benefit, please refer to Fatwa 174781.

If it has been proven by means of clear and strong evidence that the wife has committed a disgraceful offense (bringing disgrace to her spouse's honor), her denial should not be taken into account. Instead, it is incumbent on the husband to be firm in forbidding her from such disgraceful conduct. Allaah, The Exalted, made the husband responsible for his wife, her protector and maintainer. Allaah, The Exalted, says (what means): {Men are in charge of women by [right of] what Allaah has given one over the other and what they spend [for maintenance] from their wealth...} [Quran 4:34]

Therefore, the husband should advise his wife and remind her of Allaah, The Exalted. He should alienate her in bed and threaten her of divorce as perhaps she would confess her sin and express regret and remorse for what she had committed. If she does so, then it is good; otherwise, if the husband feared for his marriage and sensed her persistence in carrying on with this sinful relationship, it is better for him to divorce her.

For more benefit, please refer to Fataawa 81356 and 131584.

Allaah knows best.