Thank you for sharing this, it very much resonates with me. My husband lied and minimized for 5 years after DDay, then I got 1 year of trickle truth. I probably still don’t have the full truth. His reasoning for continued hiding and lying is basically the same as what you write about your wife (I read some of your older posts). In that sense, yes, he didn’t see the light, he felt the heat.
I’m taking this as a metaphor for inspiration vs. desperation. While both provide a motivation for changes, and they might produce very similar outcomes, there are some differences. Inspiration ("light") moves us toward that which inspires us; desperation ("heat") moves us away from something that causes despair. In that sense, desperation is a stronger motivator, as it seems to me avoiding pain is more primal than getting pleasure. However, this also means desperation provides only a short-term motivation. Once the threat is gone, it is very easy to fall back to the old way of thinking / behaving. On the other hand, inspiration provides a lasting motivation. Take for example a student procrastination. If the motivation for a change (studying) is caused by desperation (an important exam is next week, and a student wants to avoid the pain of failing the exam), then after the exam, they will most likely procrastinate again. They make a change (study) only to get away from punishment (failing the exam, failing to graduate, failing to get a good job, etc.) If the motivation for a change is inspiration, they most likely will not procrastinate again. They will not study to avoid bad consequences; they will study to move toward that what they want to accomplish, what makes them happy, what brings pleasure.
Desperation is rooted in logic, you do things out of duty, fear. Inspiration is rooted in emotion, you do things out of passion, love for something. Now, when it comes to infidelity, I believe all the negative consequences are so strong that they indeed can have a lasting effect. That is, desperation can become a long-term motivator. However, the truth is, desperate people are not happy people. Your wife (as well as my husband) should work on internalizing inspiration, for their own good.
Btw. there are more lyrics in that song that I find interesting and thought-provoking:
I said, "You know that song that Charlie Daniels did?
"About how you went down to Georgia and played fiddle against that kid?"
He said, "Yeah, it broke my heart but, you know, what're you gonna do?"
I said, "To tell you the truth, I thought your solo was the better of the two"
To tell you the truth, I also thought his solo was better of the two 
