There is helpful stuff in here, but the author clearly thinks there is only one "type" of nonmonogamy that is valid and sustainable and pushes that view hard.
I felt like this book had some helpful info and questions to suss out when thinking of your relationship. There were also some useful exercises to help you work out concepts. The thing I didn’t like is that it did not necessarily give a framework to think about stuff. Sometimes, there were open-ended questions vs examples to choose from.