[Boundless.org is part of Focus On the Family, aimed at 20-somethings. They are trying to promote marriage to that demographic.]

Lust is a sin within marriage as much as it is outside it — even lust for your spouse. That's because lust is the objectification of another. And people, beings made in the image of their Creator, aren't objects. As believers, we're called to honor one another. It's a misconception that as long as you wait till you're married, any and every mode of sexual expression is legit. Romans 12:9-10 says, "Love must be sincere. Hate what is evil; cling to what is good. Be devoted to one another in brotherly love. Honor one another above yourselves." That's no less true in marriage than in among believers in the church.