From where does a woman's desire originate, and how can this desire be fulfilled if she does not marry?

Stimulants of desire are numerous, among them: looking, thinking, idleness, watching pornography, a man touching (a woman), and touching erogenous zones.

As for what helps in overcoming desire, it is adherence to the commands of Allah and His Messenger, such as lowering the gaze, not speaking provocatively, avoiding seclusion with non-mahram (definition) individuals, occupying oneself with the remembrance of Allah and reading the Qur'an, keeping company with righteous women, and fasting frequently for those who cannot afford marriage, due to the Prophet's (peace be upon him) saying: "O young men, whoever among you can afford marriage, let him marry, for it is more lowering to the gaze and better for guarding the private parts. And whoever cannot afford it, let him fast, for it will be a shield for him."