Is the husband obligated to compensate his first wife for the days he spent with his second wife in America, given that he traveled for his father's medical treatment, and the second wife traveled with her own money, while the first wife was unable to travel due to lack of funds?

A husband must be just among his wives regarding the nights spent with each. He must compensate his first wife for the days he spent with his second wife, as there is no justification for singling out one over the other. A wife's right to equitable division is forfeited if she refuses to travel with him, or denies herself to him, or locks the door on him.