Once again, one does not need to know exactly how war feels, exactly how terrifying and horrifying, in order to understand that it is terrifying and horrifying enough that it's to be avoided. Just like cheating. You don't need to know exactly how much it hurts. So you've wasted a potentially moving soliloquy about a soldier with PTSD.
I have not mentioned "media accounts of cheating". What would those be, something like a news report on the Ashley Madison hack? Don't answer that, it's rhetorical.
I have, however, spoken of the raw emotion found in songs, poems, etcetera, that everyone has heard and anyone with sufficient empathy can understand. You insist that "the betrayer" couldn't, which of course, you'd only know if you are "the betrayer." "The betrayed" would not know the details surrounding your history of reactions to artistic expression of pain. It's not something that would normally come up in conversation. Anyway, it might be true that you couldn't understand it, which would mark you as a low empathy person, which, as I said before, means true reconcilation is probably not possible.
You've given a fatuous (and probably fictitious) example about somebody crying her eyes out over porn in order to excuse yourself for lacking empathy for people who have been cheated on. Again, this is manipulative behaviour and another example of how you make excuses for yourself, probably without even being aware you're doing it, which is why you keep insisting you don't make excuses. This, combined with the low empathy and multiple slips you've made, is ample evidence that you are the cheater, as your cheated on spouse would not be making up stories to support your rationalizations. I don't know who you think you are fooling (other than yourself of course) with this "the betrayed" and "the betrayer" dog and pony show but I've had all I can take of it. Neither of us is going to be swayed in the least and your debating style is such that you simply refuse to acknowledge points you don't have some kind of counterargument (usually involving an analogy) for, necessitating that I repeat them ad nauseum. I'm actually starting to bore myself at this point.
The answer to your final question can be found in every post I've made to you, but I'll make it clear. It's not unfathomable, it's just highly unlikely, and when combined with other things I have mentioned about the way you are communicating, it smacks of rationalization and disingenuousness. If you didn't seem so manipulative, if you'd been upfront that you were the cheater from the get go instead of engaging in defensive shadowboxing to get around telling the truth, I'd be more inclined to believe you. As it stands I'm sorry to say that I just don't believe you and there is nothing that will convince me you are being genuine other than possibly full disclosure and radical honesty from here on. You fail to see why people don't believe you, but you have been deceptive from the jump. It's not complicated. If you want people to believe you, try being open.