All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
Indeed, that person who you mention committed something that is prohibited in Islam when he lied. Furthermore, committing Zina (unlawful sexual intercourse) with this woman or living with her exactly like a married couple is even graver and its prohibition is more strictly emphasized. Allaah, The Exalted, says (what means):
· {And do not approach unlawful sexual intercourse. Indeed, it is ever an immorality and is evil as a way.} [Quran 17:32]
· {… not unlawful sexual intercourse or taking [secret] lovers…} [Quran 5:5]
The second verse means that Muslims should keenly maintain their chastity by abstaining from taking lovers and girlfriends.
As for the two children who were born out of wedlock, they should not be attributed to the biological father and they are not considered his legitimate children. Instead, they should be attributed to their mother only. Please, refer to Fataawa 83408 and 84788.
It is worth mentioning that adultery is strictly prohibited in all divine laws as underlined in Fataawa 85254 and 85425. Hence, this man should sincerely repent from what he has done. He should not take the woman with whom he committed fornication as a girlfriend.
As for his remark about the impermissibility of marrying that woman, he is the one to be asked about that issue. If a man and a woman committed Zina together and then repented of what they had done and the woman spent the due ‘Iddah (period to be waited before marrying after committing Zina), it is permissible for them to get married. The majority of Muslim scholars asserted that the prohibition of marrying the woman with whom one commits adultery is not permanent. At any rate, if you happen to marry that person and he asks you not to keep in touch with this woman and her children, you are advised to obey him in order to preserve your good relationship and attain marital stability.
It is really commendable of you to read the Quran. We hope that this will help you find the Truth and embrace Islam, the True religion with which Allaah concluded the divine messages sent to mankind. Verily, he who sincerely adheres to the teachings of Islam will attain true happiness in this worldly life and the Hereafter. Please, refer to the Fataawa 81979, 88906 and 88627 in which we have provided evidence to the fact that Islam is the true religion of Allaah. You can also refer to Fataawa 10326, 8210 and 90449 about the falseness of the present-day Christianity and the contradictions between the bibles.
Allaah Knows best.