Only the last one has any real validity, and only in a society where this sort of thing is frowned upon. One can assume that most children will be more tolerant of relationships that their parents have, unless has caused them some sort of harm, ch is certainly possible due to approbation by others.
The truth about the other four "myths' depends on the individuals concerned.
I would not be interested in such an arrangement, but I imagine that society has been a part of my aversion. Pleasing one woman is plenty difficult in most cases.
