The door of repentance is opened for an adulterer/fornicator and every other sinner. Glory be to Allah, the Most High, who 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. And return [in repentance] to your Lord and submit to Him before the punishment comes upon you; then you will not be helped”. [Quran 39 : 53 – 54]
Allah, the Glorified says in another verse: ‘Indeed, Allah loves those who are constantly repentant and loves those who purify themselves.” [Quran 2 : 222 ]’
Also, Allah, the most Glorified says : “Do they not know that it is Allah who accepts repentance from His servants” [Quran 9 : 104 ]
The conditions of repentance are to completely do away from the sin, feeling remorseful about what one has done and to promise not to return to it.
And to return things (acquired unlawfully) to the rightful owners; to make amendments on what is acquired wrongfully either what is concrete or abstract, for instance their personality/honor and the likes.