If you're a serial widower without being the cause of your spouses' deaths, then you're monogamous indeed. Monogamy does exist, and you can live morally monogamous lives although having several partners over your life.
But I don't think that's the topic. The original question was, will it become morally acceptable to be polygamous? And my answer was, you don't have to, of course, but you already can, in a contrieved way.
You can live the hookup culture without much stygma. You can dump your partners every 2-3 years, when novelty wears off, possibly having children with each of them. You can temporarily put up with a partner who doesn't satisfy you on some subjects, because you know there will be a next one who will fulfill those currently unmet needs.
TL;DR: polygamy isn't the only acceptable way, will probably never be, but some form of it already is a viable and non-stygmatized possibility.
But I don't think that's the topic. The original question was, will it become morally acceptable to be polygamous? And my answer was, you don't have to, of course, but you already can, in a contrieved way.
You can live the hookup culture without much stygma. You can dump your partners every 2-3 years, when novelty wears off, possibly having children with each of them. You can temporarily put up with a partner who doesn't satisfy you on some subjects, because you know there will be a next one who will fulfill those currently unmet needs.
TL;DR: polygamy isn't the only acceptable way, will probably never be, but some form of it already is a viable and non-stygmatized possibility.