The integrality of the gift of self
The virtue of chastity blossoms in friendship. It shows the disciple how to follow and imitate him who has chosen us as his friends, who has given himself totally to us and allows us to participate in his divine estate. Chastity is a promise of immortality.
Chastity is expressed notably in friendship with one's neighbor. Whether it develops between persons of the same or opposite sex, friendship represents a great good for all. It leads to spiritual communion.
Source: Catechism of the Catholic Church (Vatican.va)