Looking for an argument? No. Straying? No. You're just trying to justify what shes doing and have her save her skin as much as possible. "People cheat, it happens" is about as far from a solution as you can get and served no purpose. And yes, degrading. Let's not act like its suddenly a foreign concept in cuckolding. We know what goes into it.
Thing is, rather than suggest they talk about further sex lives(maybe the husband wants to sleep with other women as well or go to swingers clubs), you assume that him wanting to be a cuck is the only option. No need to break down what average means. We know what average means.
Lastly, you might be the one looking for an arguement by completely ignoring my suggestion in my earlier post or you just skimmed through it, but here it is:
"The best way forward is to stop seeing the side dude, come clean to her husband and then go from there". As analytical you are about my post, it's funny how you ignored the solution. I stated it with different wording in several posts. The bottom line is just tell the truth.
Another suggestion i mention in this current post, they both should talk about what they want sexually. Maybe the husband wants to try things with other women or even bring other people into the bedroom. If you can assume he wants something as specific as a cuck relationship, you can assume he wants to do other things sexually. The "he may want to be cucked deep down" is just an excuse to legitimize her disloyalty.
If you miss my suggestions again, I dont know what to tell you.