how can i filed for divorice from my husband who married someone else while we are still married?

Hello   I assume your facts to be that your husband "married" the working girl after your marriage to him. I am also assuming he has had sexual relations with his new "wife". If the "marriage" to the working girl occurred in MD, then it is void. If this is the case, then you can file for an immediate divorce in MD based upon adultery. You should consult with a lawyer about your rights and obligations regarding property matters and alimony.