Here are 7 Bible verses about sexual relationships from the Old and New Testaments of the Holy Bible (King James Version), sorted from most to least relevant.
Galatians 5:19 KJV
Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness,
Genesis 1:27-28 KJV
So God created man in his own image, in the image of God created he him; male and female created he them. And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.
1 Corinthians 6:9 KJV
Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind,
Colossians 3:5 KJV
Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry:
Hebrews 13:4 KJV
Marriage is honourable in all, and the bed undefiled: but whoremongers and adulterers God will judge.
Proverbs 5:15-19 KJV
Drink waters out of thine own cistern, and running waters out of thine own well. Let thy fountains be dispersed abroad, and rivers of waters in the streets. Let them be only thine own, and not strangers’ with thee. Let thy fountain be blessed: and rejoice with the wife of thy youth. Let her be as the loving hind and pleasant roe; let her breasts satisfy thee at all times; and be thou ravished always with her love.
Genesis 2:23-24 KJV
And Adam said, This is now bone of my bones, and flesh of my flesh: she shall be called Woman, because she was taken out of Man. Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.