Is a husband's searching of his wife's phone permissible or forbidden, especially when suspecting her behavior and her actions changing after marriage?

The default rule is that it is impermissible to inspect a wife's phone secretly, as it constitutes spying, which is forbidden in Islamic law. This is unless there are strong indications suggesting suspicion. If it is true that the wife incited another woman against her husband and threatened suicide, then she has committed a great evil and an unlawful corruption, which is among the major sins. The wife should be advised gently, and the gravity of her actions should be explained to her, whether it be incitement or searching for pornographic websites. This should be accompanied by prayers for her rectitude and diligence in teaching her religious matters and raising her with faith so that she may be conscious of Allah in her actions, as Allah Almighty said: {So righteous women are devoutly obedient, guarding in [the husband's] absence what Allah would have them guard}.