Against Legal Prostitution

Ross makes the argument that the law should reflect a certain notion of Christian morality:

Laws against prostitution ultimately depend on the assumption that the state has an interest in preventing serious forms of self-abuse, and that renting out your body to satisfy another person's sexual needs is a form of self-inflicted violence serious enough to merit legal sanction irrespective of why and how you decided to become a prostitute in the first place.

The trouble is: this logic applies to all sorts of consensual, private, adult behavior. Ross' and my church holds that my relationship with my husband is a serious form of self-abuse, a disintegrative relationship that destroys my soul. Why would Ross back a ban on prostitution and not on gay love? Doesn't the Catholic church argue that both are illicit instrumentalization of the body?