Bible tells us that the only sex God approves is between husband and wife.
Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge. Heb 13:4
Bible says that both fornicators (pre marital sex) and adulterers (sex outside marriage) will be judged by God.
For this is the will of God, your sanctification: that you should abstain from sexual immorality; 4 that each of you should know how to possess his own vessel in sanctification and honor, 5 not in passion of lust, like the Gentiles who do not know God; 1 Thes 4:3-5
12 All things are lawful for me, but all things are not helpful. All things are lawful for me, but I will not be brought under the power of any. 13 Foods for the stomach and the stomach for foods, but God will destroy both it and them. Now the body is not for sexual immorality but for the Lord, and the Lord for the body. 14 And God both raised up the Lord and will also raise us up by His power.
15 Do you not know that your bodies are members of Christ? Shall I then take the members of Christ and make them members of a harlot? Certainly not! 16 Or do you not know that he who is joined to a harlot is one body with her? For “the two,” He says, “shall become one flesh.”[a] 17 But he who is joined to the Lord is one spirit with Him.
18 Flee sexual immorality. Every sin that a man does is outside the body, but he who commits sexual immorality sins against his own body. 19 Or do you not know that your body is the temple of the Holy Spirit who is in you, whom you have from God, and you are not your own? 20 For you were bought at a price; therefore glorify God in your body[b] and in your spirit, which are God’s. 1 Corinthians 6:12-20
but that we write to them to abstain from things polluted by idols, from sexual immorality,[a] fromthings strangled, and from blood. Acts 15:20