The complex issue I suspect you have overlooked in your theory Fab is that actually, it really matters whether you know about an affair. You imply it "doesn't matter" whether you would know or not, because it has the same effect.
If your DP is someone who gets involved in a series of brief flings that are never mentioned or discussed, then yes, perhaps you have learned to notice the signs and can decide accordingly how you will react. Perhaps in this situation, you can "know" without it ever being acknowledged.
For people in other relationships, where monogamy is explicitly expected and there would be absolutely no expectation of "turning a blind eye" if suspicions were raised, it is different.
What tends to happen then is that because of the enormous trust default in such relationships, the deceived partner starts to feel terrible, without actually knowing why. They pin it on to other things and worst of all, they start blaming themselves. They feel their partner distancing from them and look inwards, wondering if it's their fault that they've been too preoccupied lately, too busy with work, the DCs or the extended family.
If other things have also gone wrong in recent months, such as bereavements, illness, work disappointments etc., they pin their unease and unhappiness on those issues. But at some level, they acknowledge that their feelings of misery are disproportionate to what's happened. The internal dialogue is "Yes, life has been shit for a while, but I'm surprised I feel this bad."
You suggest that the unfaithful partner knows the risk that "pulling away" causes i.e. their partner might vote with their feet. But unless this goes on for years, the deceived partner very often won't walk away. That person blames themselves, especially if they have been told that the distancing is due to work stress or some other factor. Because they love their partner, they support him/her and cut them some slack.
In even more extreme cases, the deceived partner is gaslighted by their spouse and told that any suspicions they have are paranoia. This leads to perfectly sane people feeling that they are going mad.
For a non-jealous, trusting person who has never experienced infidelity before, it matters terribly that they know about an affair. That knowledge allows the person to make choices and attribute their recent feelings of unhappiness to what was really causing it.
Now whereas unlike you, I have met several "cheerful" adulterers who really aren't wracked with guilt and misery, I agree that when essentially good people have affairs, they become terribly damaged by them. It is often overlooked that the process of deceiving and lying, if aberrant to someone's general values and character, causes a terrible conflict and dissonance. They become damaged too.
And you may have misunderstood about the advice about discussing temptations with a partner - and perhaps your dislike of drama and emotional discussions is colouring your viewpoint on this.
That discussion is not "How would you feel if I slept with someone else?" it is "I'm worried that I fancy someone else and I don't want to have an affair and deceive you. Can we talk about what this means? I know it's normal that we might fancy other people and it might be just a crush. I know that secrecy about stuff like this makes the person even more exciting, so help me get some perspective about this. I know what I'm saying is hurtful, but it's because I don't want to lie or deceive you that I'm telling you this and asking for your help. I love you and I don't want to do anything that will hurt us as individuals, our relationship and of course anything that would hurt the children."
Yes, there will be some hurt and jealousy, but nothing like the pain of infidelity and deceit.
I can't see anything In Akhems' posts that warrant being called absurd, or any fundamentalist views that might provoke stones being thrown.
The OP asked for honest advice and by and large, I think that's what she's getting.