What should a girl do who wronged the one she loves by chatting with young men and women under a false identity, and he became angry with her and left her, despite her repeated attempts to appease him, to the point that she considered suicide?

It was incumbent upon you to offer sincere repentance to Allah Almighty for the forbidden relationships, not to please a person. So, fear Allah and hasten to repent, and sever your relationship with this person, for your relationship with him, as described, is even more corrupt. Beware of the devil's discouragement, abide by the limits of Islamic law, strive to learn the affairs of your religion, strengthen your connection with your Lord, seek Allah's help, and do not despair.