I can do a repentance at one time, confess it to God, and have the blood of Jesus cleanse me, and God can now work in making the new marriage what first should have been, right?
[Rom 7:1-4 NIV] 1 Do you not know, brothers and sisters--for I am speaking to those who know the law--that the law has authority over someone only as long as that person lives? 2 For example, by law a married woman is bound to her husband as long as he is alive, but if her husband dies, she is released from the law that binds her to him. 3 So then, if she has sexual relations with another man while her husband is still alive, she is called an adulteress. But if her husband dies, she is released from that law and is not an adulteress if she marries another man. 4 So, my brothers and sisters, you also died to the law through the body of Christ, that you might belong to another, to him who was raised from the dead, in order that we might bear fruit for God.
[Rom 6:2, 7-8 NIV] 2 By no means! We are those who have died to sin; how can we live in it any longer? ... 7 because anyone who has died has been set free from sin. 8 Now if we died with Christ, we believe that we will also live with him.
[Rom 7:4 NIV] 4 So, my brothers and sisters, you also died to the law through the body of Christ, that you might belong to another, to him who was raised from the dead, in order that we might bear fruit for God.
[2Co 5:14 NIV] 14 For Christ's love compels us, because we are convinced that one died for all, and therefore all died.
[Gal 2:19 NIV] 19 "For through the law I died to the law so that I might live for God.
[Col 2:20 NIV] 20 Since you died with Christ to the elemental spiritual forces of this world, why, as though you still belonged to the world, do you submit to its rules:
[Col 3:3 NIV] 3 For you died, and your life is now hidden with Christ in God.
[2Ti 2:11 NIV] 11 Here is a trustworthy saying: If we died with him, we will also live with him;
So only one question ... Have we DIED like scripture says?
If not, then the OLD marriage is still potentially binding.
If we have DIED, and are a new person, then the OLD marriage ended with our death and we are free to remarry.
Paul is not saying you can commit adultery. Adulterers go to hell. He's illustrating our relationship to the law after dying to it and being married to Christ.