I do understand what polyamoury is. For my paper, I'm making an explicit distinction between polyamoury and polygyny because I believe that the commitment to marriage involved in polygyny makes it a separate situation.

I realize, of course, that polygynous spouses, just like dyadic spouses, can have contracts that involve non-martial sex (or - as you point out - other types of emotional relationships), but I need to limit the scope of my paper.