Look, I really don't care what kinds of "lifestyle" choices people choose to make, provided they don't demand that I approve of them or pay for their consequences.
Human nature being the stubborn and intractable thing that it is, those consequences always make themselves plain in the fullness of time, because truth cannot be held down forever.
In terms of a lifetime commitment of one's heart and soul, one man and one woman is the only union proven to work well, and it does so universally.
In terms of sheer fun, though: one man and three women...