Does men’s reaction to women cheating prove that female nature is actually known?

On average, men tend to feel emasculated, embarrassed, and generally small after finding out that their partner has cheated. For those who consider reconciliation, their first question to their wife is usually some variation of “do you think he’s better than me?”. The act almost always causes an inferiority complex (different men react differently to this) under the obvious pain of betrayal.

Around the manosphere it’s believed that female nature, namely hypergamy, is kept a strict secret and only a few men are able to “wake up” to it. However, doesn’t men’s immediate reaction to female cheating prove that it is actually inherently known? How are most men able to come to the immediate conclusion that the man his woman cheated with MUST be better (at least in her eyes)? As we know, men are polygynous; it doesn’t matter if a woman is better or worse than another; pussy is pussy. In fact, most men who cheat do so with a woman/women who pale in comparison to their partners and they admit it.

If most men don’t know about female sexuality, why wouldn’t they assume that their partners just wanted more/different sex (like they would)? Why are they so quick to believe that they traded up?