When divorce is treated as always unacceptable by Christian leaders…
anything else is acceptable.
-Lying is acceptable.
-Stealing is acceptable.
-Physical abuse is acceptable.
-Emotional belittling and vitriolic diatribes against a spouse and the kids is acceptable.
-Adultery is acceptable.
In short, any sort of sin that you can imagine is acceptable.
As long as the goal is marriage reconciliation without qualification, then the one deciding whether or not to leave holds all the power. It does not matter if you tell them if these other sinful actions are wrong. The consequences that come from divorce are known to be off the table. So, why listen? They have nothing substantive to lose.
This is part of my problem with pastors/counselors who take the firm stance against ever counseling for divorce. It is not just a positive stance in support of the marriage. Such a stance can also be a stance in favor of ongoing destructive sin. In other words, this stance can actually mean enabling and furthering sin.
Sometimes the most compassionate stance in these situations is to name the godly reality to the adulterous spouse:
Your actions may have already cost you your marriage. I will not counsel against divorce here when God has spoken through the Bible giving your spouse permission to divorce you because you chose to commit adultery. In fact, I will encourage them to consider divorce unless I see or hear evidence of repentance in you as I want no part in enabling you to continue to raping your spouse’s soul and damning your own.
And yes, the situation is that spiritually dire when adultery has happened.
Finally, I just want to point out the obvious.
Adulterous spouse’s are manipulators. Some are better than others. But all have used lies and deceit to cover their tracks or hoodwink their spouse in some way. So, a wise pastor or Christian leader will realize that the adulterous spouse may already know you are unwilling to accept divorce ever. This knowledge gives them leverage to manipulate you against the faithful spouse because they have what you want–i.e. the power over the fate of the marriage. The person with the power sets the terms. It is just how it is.
Are you willing to be party to sin?
If not, then I suggest being willing to divorce under Biblical circumstances such as adultery. Anything short of such a nuclear option is too weak a weapon to turn the battle against such evil.