Is there an expiation for fornication that led to the loss of virginity, knowing that the young man did not know she was a virgin and he deeply regrets it?

This young man has wronged himself by committing a major sin, and he must repent to Allah with a sincere repentance that fulfills its conditions: a firm resolve not to return to the sin and regret for his action. There is nothing upon him except repentance. If his repentance is sincere, it is hoped that Allah will overlook his sin and forgive him, for Allah accepts repentance from His servants and pardons evil deeds. Allah says: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'" (Az-Zumar: 53).