A Muslim woman is not allowed to marry a non-Muslim man whatever his religion is. There are clear and explicit Islamic injunctions on this point in both the Qur’an and the sunnah. Allah the Almighty said: “…and do not marry (your girls) to idolaters until they believe…” (Al-Baqarah:221) And He said concerning the immigrant Muslim women: “Then if you know them to be Believers, do not send them back to the unbelievers. They are not lawful for them (as wives), nor are they lawful for them (as husbands).” (Al-Mumtahanah: 10)
So, for the validity of marrying a Muslim woman, the husband has to be a Muslim. This issue is not subject to compromise.
When a Non-Muslim converts to Islam he may face some problems with his family and relatives. The attitude he has to observe in this case is to remain patient and to keep good ties with his parents and kin and perhaps with his good Islamic character they become convinced with the teachings of Islam. Allah the Almighty said: ” And We have enjoined man in respect of his parents– his mother bears him with fainting upon fainting and his weaning takes two years– saying: Be grateful to Me and to both your parents; to Me is the eventual coming. And if they strive with you that you should associate with Me what you have no knowledge of, do not obey them, and keep company with them in this world kindly, and follow the way of him who turns to Me, then to Me is your return, then will I inform you of what you did” (Luqman 14-15)
As for the children of the converted Muslim, if they are still young and below the age of puberty, they become naturally Muslims. Muslim jurists hold that young children becomes Muslims once one of their parents converts to Islam. However, if these children are adults, he should keep good relations with them and call them to Islam first by his good manners and by all kind approaches.