Is it permissible to supplicate against one who has caused emotional and moral injury, and what must be done to expiate the sin, and will the repentant person be held accountable for their sin on the Day of Judgment?

The mixing of men and women is not permissible, even if it is for the purpose of marriage, due to the strife and corruption it leads to. The questioner must repent to Allah for what she has neglected, and she has no right to supplicate against this man. She should busy herself with actualizing repentance. If she is sincere in her repentance, Allah will accept it and will not punish her for this sin. Rather, He rejoices at the repentance of His servant and loves those who repent, and He replaces their evil deeds with good ones, for the Messenger of Allah, peace and blessings be upon him, said: "The one who repents from sin is like one who has no sin."