What is the ruling of Islamic law on marrying a young man who is three years younger than me and of a different nationality, after I became pregnant by him and desire to conceal my sin and repent?

The relationship between a man and an unrelated woman is a gateway to the devil's machinations, and can escalate from conversation to adultery. For this reason, Islam forbade approaching adultery because it is a great abomination that carries severe punishments in this world and the hereafter.

However, Allah has opened the door of repentance for those who sincerely repent, which involves abandoning the sin, regretting it, and resolving not to return to it.

It is not permissible for adulterers to marry each other except after sincere repentance. Similarly, it is not permissible for an adulterous woman to marry someone other than the adulterer until her womb has been cleared by the completion of a pregnancy.

Whoever falls into this abomination must inform the wise members of their family to help them resolve the problem. Repentance erases the sin, but the effects of the sin may remain and require wise handling.