God's first commandment was: "Be fruitful & multiply! (Gen: 1:28) He did not ordained "get married and "then" have sex!" Sex was created & instituted by God in the very beginning! God is the author of genuine pleasure, genuine happiness, genuine fleshly satisfaction, even sex!
All things were made by Him & without Him was not anything made that was made. (Joh. 1:3) Including your sexual organs, your body, and every part of you. If sex is sin, then God is a sinner, because He made it, & He created us to have and enjoy it!
Sex was not the Devil's idea, contrarily to what most people think -- it was God's! And the Devil is its(sex) arch-enemy because it encourages the growth of the Kingdom of God! The Devil tries to take the credit for it, and then turns around & condemns you for enjoying it.
God created sex , not Satan! God is the One Who made those sexual organs & every single nerve that feels so good! He's the One Who dreamed up sexual pleasures & bodily contact & God Himself created that marvellous final explosion called the "orgasm"!
God is the God of the body, the God of sex -- He made your flesh in His image! God created man in His Own image, in the image of God created He him; male and female created He them. (Gen. 1:27) So, Praise God for sex! Amén? ... He created it!