I found the article Why So Many People Care So Much About Others’ Sex Lives interesting. It referenced this study which concluded:

At the individual level, perceived female economic dependence explained significant variance in anti-promiscuity morality, even after controlling for variance explained by age, sex, religiosity, political conservatism, and the anti-promiscuity views of geographical neighbors. At the state level, median female income was strongly negatively related to anti-promiscuity morality and this relationship was fully mediated by perceived female economic dependence. These results were consistent with the view that anti-promiscuity beliefs may function to promote paternity certainty in circumstances where male parental investment is particularly important.

That would imply that people would be more likely to participate in the lifestyle when women are more likely to have their own jobs and able to support themselves. It is certainly true that nearly all of the women I know in the lifestyle have their own jobs. But I don’t know that much about women who are not in the lifestyle. It could be that most of the women I happen to know are capable of being independent.