I highly doubt that. Most males seem to experience some degree of sexual jealousy towards their mates (how many women have been murdered or assaulted by their male partners over cheating? A lot).So you think just as many men will be willing to share one wife with other men as there are women willing to share one man with other woman. Interesting assumption. On what rational basis do you make it?
Or, perhaps you would actually force surplus men into sharing one woman in order to solve the problem?
The polyamrous crowd seem to forget that we're apes first and foremost and we seem to have more in common with the violent chimps than the peaceful bonobos. Way too idealistic. Also, women having multiple husbands has been very rare in human cultures. Let alone all the other combos that people fantasize about. 99% (give or take) of the time, "plural marriage" means one man and multiple women. Anyway, I doubt plural marriage will ever be legalized. They'd have to rewrite so many laws for it, to start with. Polygamy has never been an accepted practice in Western culture. Gay marriage has more historical precedent.