You say that a divorce is ok if it is a biblical divorce. You say the reason for a biblical divorce can be marital unfaithfulness. Jesus says that any one who looks on someone with lust in their heart has already committed sin. Since just about every married human in the world has committed adultery under this guide line, then saying that the only people who can get a biblical divorce are the ones who have had adultery committed by their partner is like saying the only old people allowed in this nursing home are people with gray hair. Point! Why would Jesus say the only way you can get a divorce is if you have experienced what EVERYONE has experienced?
Should everyone receive capital punishment as a murderer because we have been angry at someone (Matt. 5:21-22)? Jesus’ point about anger and lust (Matt. 5:21-32) is that God is also concerned about the sin on the inside. Some of the religious leaders focused on the external actions and believed it was acceptable to lust and hate on the inside. Jesus corrected that thinking. Jesus condemned lust on the inside when He said,
. . . everyone who looks on a woman to lust for her has committed adultery with her already in his heart. (NASB) Matthew 5:28
That was the internal act of sin. To follow through with our internal sinful desires is the second stage in our sin and causes other things to happen to us.
And it was said, ‘WHOEVER SENDS HIS WIFE AWAY, LET HIM GIVE HER A CERTIFICATE OF DIVORCE’; but I say to you that everyone who divorces his wife, except for the cause of unchastity, makes her commit adultery; and whoever marries a divorced woman commits adultery. (NASB) Matthew 5:31-32
Not everyone follows through with their lust or even a stated desire. If they do so and then divorce, Jesus says they do not have a biblical divorce – they are not free to remarry unless the conditions are correct. There is a consequence to acting on our desire. Jesus did not say “everyone who divorces his wife, except for the cause of LUST . . .” He specifies a physical act. There is a difference between an internal sinful urge and following through with an outward act. God will judge us for the internal act AND the outward act, but the outward act has much more serious consequences.
The outward actions are a response to the inward sinful attitudes and desires.
But the things that proceed out of the mouth come from the heart, and those defile the man. For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders. (NASB) Matt. 15:18-19
But we do not have to yield to sin and commit the external act.
Let no one say when he is tempted, “I am being tempted by God”; for God cannot be tempted by evil, and He Himself does not tempt anyone. But each one is tempted when he is carried away and enticed by his own lust. Then when lust has conceived, it gives birth to sin; and when sin is accomplished, it brings forth death. (NASB) James 1:13-15
Divorce involves a physical act, a piece of paper called a certificate – an external act and an internal act of sin. Lust is only an internal sin. Jesus condemned both! But only the external act can prevent remarriage, according to Jesus.