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.
A husband is neither obligated to travel with his wife for Hajj nor to bear her expenses for Hajj. Rather, this is considered as an act of charity and goodness from him and it is not an obligation on him to be just between his two wives about it. The justice that a husband is obligated to fulfill is in regard to staying overnight with each of them and spending on them the obligatory spending; for more benefit, please refer to Fatwa 160503.
However, it should be noted that a husband is not permitted to travel with any of his wives without either casting lots between them or having their consent. In case he travels with one of them without doing so, then he has to make up that period for his other wives. For more benefit, please refer to Fatwa 86264.
Allaah Knows best.