I think the idea that cuckoldry would be a non-issue if people were thinking clearly is pretty close to conventional ideas about adoption-- that people shouldn't use biological descent to make distinctions among the children they're raising.

I think folk morality only says that if you adopt kids, you should treat them equally to your biological kids. It doesn't say that people who have biological kids instead of adopting are bad people.

To extend the idea, we could say that just about all the pain people feel about status-lowering events is self-fulfilling prophecy

Why do you single out status-lowering events? You could go further and say that anything that doesn't cause physical pain is okay, e.g. stealing someone's car is okay because the victim theoretically could brainwash themselves to not care about material belongings.