All Sunni schools of jurisprudence agree that zināa is to be punished with stoning to death if the offender is a free, adult, married or previously married Muslim (muhsan). Persons who are not muhsan (i.e. a slave, a minor, never married or non-Muslim) are punished for zina with one hundred lashes in public and one year of banishment.
- Ibn Hajar al-Haythami said in al-Zawaajir ‘an Iqtiraaf al-Kabaa’ir (2/138):
Thus it is also known that there are different categories of zina. If it is done with a non-mahram woman who has no husband it is a serious matter. It is more serious if it is with a non-mahram woman who has a husband; it is more serious still if it is with a mahram. The zina of a previously-married person is worse than zina of a virgin, which is indicated by the fact that the punishment is different. And the zina of an old man who is of sound mind is worse than the zina of a young man, and the zina of a free man or a knowledgeable man is worse than the zina of a slave or one who is ignorant.
And come not near to unlawful sex. Verily, it is a Faahishah (i.e. anything that transgresses its limits: a great sin), and an evil way (that leads one to hell unless Allaah forgives him) [al-Isra’ 17:32]
may Allah have mercy on you and guide you to the straight path.
Allah knows best.