…do not be unfaithful to the wife of your youth.
-Malachi 2:15b, NIV
Whether it is their conscience or the demonic, I do not know. What I know is some cheaters despise reminders of God’s condemnation of their infidelity.
They rage and strike out verbally when reminded what they are doing is wrong in the eyes of God. Cheaters might even attempt to call the faithful spouse “abusive” for reminding them of such moral laws.
This is part of the reason that I do not buy the “mistake” narrative cheaters use to “excuse” their behavior. They know what they are doing (and know it’s wrong)!
They are seeking affirmation. To be reminded of their obligation is a buzz kill. They do not like it.
Honestly, you are wasting your time with such a person at that point. They are committed to their lies and sins. Their moral ship is sinking. It’s best to get off while you can via divorce (see Mt 19:9).