How can one quit masturbation, and does its addiction cause sexual frigidity or affect the hymen, and what is the way to sincere repentance from it?

Repentance from masturbation must be out of sincerity to Allah and fear of His wrath, not out of concern for health. One must not despair of the acceptance of repentance, for Allah accepts the repentance of His servants, and He is Forgiving and Merciful. The one who repents from a sin is like one who has no sin. As for detailed questions about frigidity, virginity, and similar matters, the specialized counseling section can be consulted.