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 is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
First of all, we congratulate you upon embracing Islam and we ask Allaah to make you firm and steadfast on this religion until the Day you meet Him. Besides, we congratulate you for migrating to a Muslim country and we wish you all the best.
As regards your enquiry, you have to know that is not permissible for a married woman to marry another man until her first husband divorces her, or dies, or that their marriage is invalidated. Therefore, since you are still a wife of this man, then it is not permissible to marry another man, however, you may take your case to an Islamic court in this Muslim country to remove the harm from you [to grant you a divorce]. This is of course if this man is a Muslim, but if he is a non-Muslim, your marriage to him became void as soon as you embraced Islam, unless he became a Muslim while you are still in the waiting period. In this case the marriage is still valid according to the most preponderant opinion of the scholars. So if we suppose that your marriage to him has become void, it is permissible for you to marry another man when your waiting period ends, however, it is more appropriate to take your case to an Islamic court in order to remove the embarrassment from you.
Finally, it should be noted that the presence and consent of the guardian is a condition for the validity of marriage, so if you have no guardian, the Muslim ruler or a person who could act on his behalf, like the judge for example, would marry you off.
Allaah knows best.