Praise be to Allaah.
It is true what you have said, that wrong is wrong. In Islam, pre-marriage
relationships are not permissible. We believe that adultery is not permissible not only in
Islam, but also in all religions of Allah (God). I believe that the gentleman of
nationality XXX whom you are seeing is not serious in getting married, because if he were,
he would have married you from the very beginning. In Islam, a man must respect the will
of his parents, and in some cases he must obey them. You, in your present status, are not
a member of his family. When you become his wife, then you are considered to be his
family. Yet even then, if a father orders his son to divorce his wife because, for
example, she has bad reputation or she is not a good Muslim, he must obey his father. My
advice to you is to think seriously in embracing Islam, not for the sake of this man, but
for the salvation of your soul and body from Hellfire. I believe by now, you have a good
idea what Islam is, putting aside the bad example this gentleman has been setting.
Therefor, you should stop seeing this man and you should become Muslim. If his love to you
is genuine, he will propose to you. If he doesnt, then be sure that Allah will not
leave you alone, and as He guided you to his religion, He will send you a good Muslim who
will cherish you and give you a decent life as a wife not as a mistress. I pray to Allah
that He may enlighten your heart with Islam and guide you to make the right choice.