Sex is, a gift from the Lord. To be confined to the marriage bed. All other is sin.
Words have definite meanings. You are saying all sex outside of marriage is sinful and again your are not excluding nonconsensual sex such as rape and incest.
Since any religion and, in fact, all religions are merely hypotheses, you are welcome to believe in one absolutely but you are not free to bind others to the rules or beliefs of a religion.