Lulz & whatever.
Core message of the book: heterosexual sex is the greatest achievement of the universe.
Alien races have “procreation” and “growing closer,” but human-kind has the crowning jewel of the entire cosmos: P-in-the-V sex.
Secondarily, monogamy is a symptom of the jealousy disease that keeps us from experiencing the perfect nirvana of straight polyamory.
If you can get over all that and the rampant sexism and misogyny, it’s an otherwise fun book. Lulz & whatever. Other reviews will probably spoil the plot and themes better than I could.