When Pope Francis released a widely anticipated document on family life last week, he didn’t just weigh in on controversial topics like whether remarried Catholics may take communion (maybe) and whether the Catholic church will approve gay marriages (definitely not).

He said something more likely to be overlooked but also very unusual for a Catholic leader: He wrote about the joy of sex.

In the document, called Amoris Laetitia, Francis frankly addressed sex as a practice married couples work at over a lifetime. His approach to sex and contraception is notable for its affirmation of sexual passion, its realism about what can go wrong in marital relationships and its focus on growing in intimacy. All three are unusual in official Catholic teaching.

The pope wrote in this apostolic exhortation that he seeks to avoid continuing a tradition of “almost exclusive insistence on the duty of procreation” combined with a “far too abstract and almost artificial theological ideal of marriage.”

His more earthy vision of marriage links the “one flesh union” mentioned in Genesis with the love poetry of Solomon’s Song of Songs and a provocative phrase from Psalm 63: “My soul clings to you.”

Citing these texts, Francis paints a vision of a loving union of two spouses whose passion is an “icon” or symbol of God’s own inner life. Yet, he insists, it is always imperfect, always a work in progress.

He affirms sexual desire, giving and receiving in sexual encounter and the self-transcending passion attested to by the great mystics of the Christian tradition.

Francis does not abandon his predecessors’ teaching that sex is meant for procreation. He briefly references Humanae Vitae’s ban of contraception on the grounds that the unitive and procreative meanings of sex are inseparable. Francis clearly states that “no genital act of husband and wife can refuse this meaning.”

The document will disappoint those who hoped the pope’s recent comment that contraception might be acceptable to prevent the spread of Zika, or his earlier claim that Catholics are not required to “breed like rabbits,” indicated an opening on the morality of artificial birth control.

But Francis justifies the prohibition of contraception by putting it in a far more positive context than did earlier Catholic leaders. Unlike Pope John Paul II, who characterized contraceptive use as a selfish manipulation and degradation of human sexuality, Francis paints an attractive picture of a love so intense that it seeks to go beyond itself.

Children, he says, are living reminders of deep married love. Sex is fundamentally passionate and essentially fruitful. Francis’s focus is on the positive connection between life and love.

Despite his affirmation of love, Pope Francis is realistic.

He recognizes the violence and domination that can distort sexual relationships, even in marriage. He says, “We also know that, within marriage itself, sex can become a source of suffering and manipulation.”

These sexual sins receive much more attention in his document than the hot-button issues of contraception and same-sex marriage.

Francis is also realistic about social pressures that make passionate marriage difficult to sustain. He worries about a growing “inability to give oneself to others” or commit to the hard work of improving imperfect marriages.

During the synods on the family that preceded Amoris Laetitia, some leaders in the Church urged the pope to be more critical of modern society and to clearly state the superiority of Catholic doctrine. But Francis avoids simplistic, sweeping judgments of cultural views. He says family is “not a problem” but an “opportunity.” He is realistic, but not pessimistic.

Francis describes marriage as a vocation and intimacy as something couples work on and grow into overtime.

He stresses the importance of a sexual relationship in the life of couple. Over and over, he urges married people not to give up when physical attractiveness fades or passion wanes. Rather, they should enter more deeply into their shared life. Since sex is an essential part of that sharing, Francis says, couples ought to pay attention to it.