Why didn't Allah keep the questioner away from her manager before the scandal, sin, and divorce, and shield her by her marriage to her ex-husband? And what is the purpose of all that happened?

Sincere repentance is obligatory for negligence, dereliction, and transgression of God's limits in mixing with the manager. This repentance must involve abandoning the sin, regretting it, and resolving never to return to it. It is not characteristic of a truly repentant person to blame fate; rather, they blame themselves and acknowledge their failure in fulfilling God's rights. If repentance is sincere, then God conceals the servant's faults and transforms their evil deeds into good ones, for "one who repents from sin is like one who has no sin."