Does a wife's addiction to chatting with foreign men via social media—despite her repeated repentance—indicate Allah's wrath upon her, and what is the expiation for this sin?

You must hasten to repent to Allah Almighty for forbidden conversations with men. Repentance is by abandoning the sin, regretting having committed it, and resolving not to return to it. Among the signs of sincere repentance are avoiding the causes of disobedience, cutting off the paths leading to it, eradicating the root of evil, being wary of following the footsteps of Satan, and striving in righteous deeds. You must be careful not to let Satan and his whispers of despair discourage you, for a sound repentance is accepted and erases what came before it. The one who repents from a sin is like one who has no sin, and Allah rejoices at the repentance of His servant and replaces his bad deeds with good ones.