Polyandry, polyamory or polygyny?

Yes, this would explain why those highly polyandrous species of insects, such as ants, wasps, and bees that have one reproductive female serviced by hundreds of males have been so unsuccessful, are so rarely sighted, and are on the verge of extinction. Rrhain's response in Message 7 should have closed this topic.

I'm not sure I follow the logic here. Is a man's best strategy to pass one of his sperm cells to each of 100 million women (every day)? And is a woman's best strategy therefore to have a different mate every month, at least until she gets pregnant?

As I pointed out in message 10, there are a great many very successful species that have been around a lot longer than humans and that are also very diligent in raising their children, e. g., ants, wasps, bees, elephants and many, many others but in which the females (or female, i. e., the queen in the case of ants, bees, etc.) are polyandrous - mate with many males. In many of these species, the females simply don't rely on the male to provide any help in child rearing - they are helped by other females in the herd, hive, or whatever the social group is called.The point is that monogamy is just one of a broad suite of strategies in play for various species that invest heavily in the rearing of juveniles.