What is the Shar'i guidance for dealing with intense desire for women and the difficulty of lowering the gaze, given the circumstances of being unable to marry a second wife and the opposition of the first wife, along with the impact of this on religiosity and the practice of masturbation?

To deal with human desires, remember that Allah is aware of you, and He has commanded lowering the gaze and guarding one's chastity, for that is purer for the soul. Occupy your tongue with dhikr (remembrance of Allah), your heart with contemplation, and your limbs with acts of obedience, so you may emerge from heedlessness and spiritual death. Study the lives of the Companions and the righteous to draw lessons from their struggle against their own selves. Increase in fasting, for it is a bridle for the soul, and if you are able to marry, do not hesitate. Remember that death is coming, so be prepared and do not be deluded by a fleeting desire.