What is the ruling regarding a husband favoring his second wife by going out with her alone, frequently calling her, and expressing his feelings to her, while falling short in these aspects concerning his first wife, and what does this cause in terms of jealousy?

The basis for equitable division among wives is the night, with the day being secondary to it. It is not permissible for the husband to enter upon his other wife during the daytime of the wife whose turn it is, except out of necessity, nor at night, except out of dire need. If the husband goes out with his other wife for a stroll on your appointed day, or contacts her for no need, he is doing wrong and being unjust, and his justification of her young age is unacceptable. However, his going out with her on her own appointed day is permissible. And while he is not obligated to do the same with you, it is nevertheless advisable for him to do so as part of living together honorably, as it fosters harmony and affection. It is recommended to engage in a good dialogue with the husband regarding these matters and to seek help from close relatives if necessary.