sex trafficking is a business and like all businesses, the success is based on demand and supply.  to destroy a business (illicit ones) you must either kill the demand or supply, maybe both.  to decriminalize prostitution by the supplier will not stop it, it will only encourage it.  prostitution will encourage more people to engage in sex outside of marriage and promiscuity.  your policy encourages these behaviors.  Was not the fall of Rome due in part by sexual promiscuity?  Is promiscuity good for any society?