Thou shalt not commit adultery.
-Exodus 20:14, KJV
Funny how “Christian” folk are swift to condemn divorce but slower and “nuanced” when it comes to condemning adultery.
I think such is a sign of immaturity, minimally. It may even be a sign of someone not truly knowing God as God’s heart on these matters could not be more different.
A mature Christian will understand that divorce is what needs nuance and adultery demands unqualified condemnation.
Godly choices to divorce exist. We see this throughout the Bible. God choices to divorce a cheating Israel (see Jeremiah 3:8), and Jesus permits his followers to divorce in the case of sexual immorality (see Matthew 5:32 and 19:9).
That said, some people divorce in order to marry a more desirable partner. That would be to commit adultery in another form in the eyes of God. The Bible does not permit divorce of one’s spouse because you are tired of him or her. Hence, a nuance approached divorce is warranted.
Adultery is always wrong, though.
It made the Ten Commandments as a prohibited act with no qualifications. Divorce did not.
A person committing adultery is a person in grave spiritual peril. They need “strong medicine,” not weak-kneed, hand-holding and enabling. Talking with them about why they “had to” sin is ridiculously foolish behavior.