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 thank and praise Allaah Who guided you to Islam and we ask Him to make you firm and steadfast on His Religion until the Day you meet Him.
We advise you to seek beneficial knowledge, perform good deeds and befriend righteous and pious women, as these are the best things that help a Muslim woman remain steadfast on her religion.
You should know that it is not permissible for a Muslim woman to have an affectionate relationship with a non-Mahram man [a Mahram is a husband or a person whom one is permanently prohibited from marrying due to suckling, marital, or blood relations]; for more benefit, please refer to Fatwa 81356.
The best solution for the people who love each other is marriage. Therefore, if this man can marry you then this is good. If he marries you, it should be with the consent of your Muslim guardian and the presence of two witnesses; for more benefit, please refer to Fatwa 83629. If you do not have a Muslim guardian, then please refer to Fatwa 88488.
Nonetheless, a husband is not obliged to inform his first wife or seek her permission in order to marry a second wife. He is only obliged to fulfill their rights and be just between them, as we clarified in Fatwa 82988. You may also choose to renounce your right on him in spending the night at your residence, and he may come and visit you during the day only.
You should know that in Islam the wife is entitled to a dowry which the husband is obliged to pay her; Allaah Says (what means): {And give the women [upon marriage] their [bridal] gifts graciously.}[Quran 4:4]
However, it is permissible for the husband to teach his wife the Quran or a chapter of it and consider this as a dowry, or even a subject about religious knowledge, and the like.
It should be noted that if marriage does not take place between you and this man, you should cut any relationship with him. Forgetting him is possible if you sincerely intend to do it. For more benefit on how to treat love sickness, please refer to Fatwa 84544. It might be that Allaah will facilitate for you a pious husband and you may seek the help of your Muslim sisters in finding one.
A Muslim woman should not absolutely refuse to marry, as this is contrary to the guidance of the Prophet because if she does so, she may be tempted to commit illicit sexual intercourse. Marriage is an obligation on whoever fears to be tempted to commit illegal sexual intercourse.
Allaah Knows best.