I'm not convinced. Yes, they do, because in Western societies that is the main option (thanks to monogamy mandated Christiantiy, presumably). That doesn't imply it is their preference.

Maybe their preference would by monogamy - with George Clooney. But since that is not an option, the bets are off. In general, there may not be enough rich men willing to take on multiple women for a significant number of women to choose that option.