> They have made the decision that going to the effort of getting rid of jealousy – of dealing with the pain of their partner spending the night somewhere else – is not worth the benefits they might gain from nonmonogamy.

This is about the equivalent of saying that people who decide to eat 3 meals a day are insecure about dealing with the negative emotions of being on a continual starvation diet.

Maybe the author should just try owning their position like "yea I want to sleep around and feel good about myself" instead of having to tear others down.