All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
First of all, we would like to thank you for your trust in us and for directing your inquiry to us. Marrying that man, whom you love, and going back to him is a simple matter. Marriage is the best advice for those who are in love. The Muslim man is allowed to marry a Christian or Jewish woman provided that she is chaste, as we have explained in fatwa 82067. Also, there are certain conditions for a marriage contract to be valid in Islam, and among these conditions are the presence of the bride's Wali and two trustworthy witnesses, as has been underlined in fatwa 83629.
Instead of focusing on this, let your concern be for considering converting to Islam, and do not regard it as a difficult matter. We believe that you are an intelligent person, and we hope that your mind would lead you to the truth. Our advice to you is to turn to Allah and ask Him to guide you to the straight path. You should reflect on your current religion and think about the falsehood and contradictions in the many versions of the Bible which indicate that it is false and that repentance and conversion to the true religion are a must. Please refer to fatwas 8210, 10326 and 90449 about the falsehood in the current Christian beliefs.
Islam is the true religion that guarantees genuine happiness in this worldly life and the Hereafter. It is the last and concluding divine religion by means of which Allah, The Exalted, abrogated all the previous religions; He does not accept any other religion. Please refer to fatwas 88906, 88051 and 111063 about the evidence proving that Islam is the true religion.
We hope that if Allah guided you to Islam, this man would accept you as a wife and you would find happiness together, hopefully soon.
Allah knows best.