The book review states
But if we are to judge by letters printed in the slick magazine, "Mr.,* partner-swapping (as it s should be more accurately de scribed) is prevalent in almost every town and city in this country. Now many of the letters are gathered together in a book, "WIFE-SWAPPING; A Complete 8-Year Survey of Morals in North America* (Counterpoint, Inc., N.Y., 95?), and they have the ring of authenticity.
The possibilities for sexism are still there, but, maybe don’t judge a scene by it’s cover?