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.
First of all, we inform the questioner that there is nothing in Islam called friendship between a woman and a non-Mahram (marriageable) man. Such friendship is foreign to Islam which is promoted by the enemies of Islam in order to spoil people’s morals and open before them the doors of temptation. Such relationships detach them from the rules and regulations which maintain the dignity and honor of societies and which guarantee tranquility for such societies and protect them from the swamps of immorality and animalistic chaos.
So, we advise the questioner to repent to Allaah The Almighty from what she referred to as friendship and to keep away from non-Mahram men including her fiancé until a valid marriage contract under the Sharee‘ah (Islamic law) is concluded.
Merely saying that someone is her husband for a certain reason does not result in the conclusion of marriage under the Sharee‘ah (Islamic law) even if this is done in front of people. There are conditions that must be met in a marriage; mainly the guardian of the bride and two witnesses; otherwise, it is invalid. Hence, this man is a non-Mahram to you and you are not lawful for each other.
Allaah Knows best.