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 (saw) is His slave and Messenger. First of all, we ask Allaah to reward you for being keen on calling people to Islam and we ask Him to protect the religion of this sister and bless her with a pious husband. There is no doubt that being just between wives is a condition for marrying more than one wife. In principle a husband should be just between his two wives even if they are in different countries, as stated by some jurists . This is in case the husband is able to be just between his two wives who are living in different countries. However, if he is unable, he should fear Allaah as much as he can. Therefore, if you wish to marry this woman, it is permissible for you to marry her, because not marrying her will not benefit your first wife in anything. However, you should travel to your first wife whenever this is possible and give her as much as you can from your time. Allaah Knows best. (Source: islam_web) Classified in Women and Family > First Steps to Marriage