Sigmund freuds whole oedipus complex thing makes a lot of sense- not as a general psychological framework, but as a framework for freud himself.
Freud was the product of a second marriage, with a dad ~60, to mom being g in her 30s. His dad had 2 sons from that first marriage who were also in their 30s. With father was also a trader, meaning he was likely on the road a lot.
So, when a young freud looked to his brothers to model behavior from, he saw their interactions with his mother, an age peer of the opposite sex, as opposed the normal generational gap others see between their siblings/peers and their mothers, one that was likely a lot more sexually charged than the normal.
These interactions, instead of the normal age reverant ones, are the ones freud seems to have internalized, and then assumed everyone had, and based his oedipal complex on.
Now, tbf, both brothers were married, and iirc, neither lived at home during freud's childhood, so the behavior could have been a bit less direct; at social gatherings, his mom would have likely been grouped in with the brothers' wives, being a married woman the same age, as opposed to the married women his father's age.
The brothers' wives then, to Freud, could have been seen as sort of proxy mothers, and the effect is still the same; Freud could have seen his brothers pairing up with others in his mom's group, and modeled his behavior off of that.
But occams razor still has freud walking in on his mom schtupping one of his brother during his formative years.