Does God accept the repentance of a young man who engaged in an illicit sexual relationship and became accustomed to wrongful practices, and how should his repentance be, and is there a way to rid himself of this addiction?

If someone commits a sin, they must conceal it and sincerely repent to Allah, without disclosing it to anyone. This is based on the Prophet’s (peace be upon him) saying: "Avoid these abominations that Allah Almighty has forbidden. So, whoever falls into any of them, let him conceal himself with Allah's concealment and repent to Allah." The door of repentance is open until the sun rises from the west. And it is impermissible to discuss sexual practices with one's fiancée before the marriage contract.