Answer
According to Shari?ah, a female may have only one husband at one time. It is not permissible for you to marry another man while being married. The marriage will be invalid. Any relationship with any man while being married will be Zina (adultery) which is a major sin.
You should terminate your relationship with the person and repent to Allah. Make a firm intention never to engage in such a relationship in future. These are the blessed days of the year and you should take advantage of the Barkaat and blessings of such days and repent to Allah and reform yourself.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai