Lust, the sexual using of others, particularly for sexual desires, is undeniably rampant in our society. Pornography, hook-up culture, the bed-buddies relationships, all of which are seeking self-gratification rather than a partnership with another. Specifically, lust is intense craving or desire normally about sexual desires.
Culturally, we are all struggling with this particular footfall. It may not be blatant, it may those hot and heavy romance novels. Lust isn't necessarily physical, It can be an emotional lust; day-dreaming about man who would treat you much better than your husband. But like the other five sins we have considered, the crux of lust is a focus on self and self-indulgence.
As Catholics, we have our own unique take on lust. Lust is not simply sexual desires; it is self-indulgent sexual desires. St. Pope John Paul II wrote about this in his book, The Theology of the Body. The basic premise he puts forth is that sexual desire at its purest form, that is open to procreation, is a celebration of love and what God intended for married couples. Sexual desire is a natural, normal part of the human experience. What is unnatural is seeking to sexual gratification without recognizing what it actually means. A sign of the true unification of the couple, who is literally one person in God's eyes.
What does this mean for us? It means that those called to the married vocation are supposed to have sex and celebrate that. It also means that God understands that we will struggle with sexual desires. The sin arises when we act on them, focusing on ourselves and on our needs.