26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
-Hebrews 10:26-27, KJV
When professing Christians choose to cheat, these verses highlight the serious nature of such persistent sin.
Adultery involves a pattern of sins. It involves lying, idolatry, and sexual sin to name a few. To choose an affair partner is to sin willfully. It fits the dire pronouncements about Christians in these verses from Hebrews 10.
This is why I am rather skeptical regarding a reformed Christian cheater.
The Christian already knew cheating and lying was wrong. However, they persisted in the sin. In other words, it was willful. That is a much deeper problem than someone sinning out of ignorance (as if a cheater really is ever ignorant. I am doubtful of that!).
