A great explanation of what chastity really is from Carl Anderson’s book Called to Love: Approaching John Paul II’s Theology of the Body (p.150):
Real chastity has nothing to do with so-called “puritanism,” but is a life-affirming self-mastery in love. Chastity is the fruit of Christ’s gentle education of the heart, which gradually shapes the heart’s desires and feelings into a reflection of true love for others.