What is the ruling regarding a relationship between two individuals who consider themselves married before God, and exchange sexual conversations based on this belief, with the intention of marriage, and do previous sins affect the acceptance of repentance and the performance of religious obligations in this case?

The relationship between a woman and a man who is not her mahram is forbidden (haram), and it is among the steps of Satan that lead to zina (fornication/adultery). The ruling does not change if the man intends to propose to the woman; it is not permissible for her to be in khalwa (seclusion) with him, or to display her adornment (zinah), or to speak softly, let alone discuss marital relations. Considering her a wife before God is ignorance and temptation from Satan, for a woman does not become a wife until after a valid Islamic marriage contract (nikah).

Islamic law has set boundaries for interacting with a non-mahram man to preserve a woman's dignity and honor, and to protect society. These include: adhering to the prescribed hijab, as in His Almighty's saying: "And not expose their adornment except that which [necessarily] appears thereof," and His saying: "And to draw their headcovers over their chests"; and adhering to modesty and decorum in speech, avoiding softness and allure, as in His Almighty's saying: "Then do not be soft in speech [to men], lest he in whose heart is disease should covet, but speak with appropriate speech"; and not being in khalwa with him.

Khalwa accompanied by discussion of marital relations is more heinous and repulsive, and if it involves physical touch, the sin is even greater. Therefore, one must fear Allah, abandon this relationship, and repent. The suitor is a stranger to his fiancée until the contract is concluded. It is only permissible for him to look at her if he intends to propose. If he has proposed, it is forbidden to look at her (in an unrestricted manner).