Is it permissible for a Christian woman who separated from her husband ten years ago without legal proceedings to marry a Muslim man while she intends to convert to Islam, with her first marriage remaining valid?

If the wife embraces Islam but her husband does not, until her 'iddah (waiting period) expires, then she is permitted to marry someone else. Alternatively, she may wait for him, hoping that he might embrace Islam. In the case where the wife embraces Islam and her 'iddah expires without the husband embracing Islam, the marriage is فسخ (dissolved) from the moment she embraces Islam, without the need for a divorce. She can then marry a Muslim man. The 'iddah is calculated from the time the wife embraces Islam, lasting for three menstrual cycles, or three months, or until she gives birth if pregnant.