Peoples saw the poly and think it was forshadowing, completly forgetting the others forms of relations we've seen. Man, just because they see poly doesn't mean it was the end point at all. It was to show her another form of love. I think it's better that she choose her own form of love, instead of choosing one just because she saw it.
Really, just accept the outcome without throwing assumptions about what the author supposidly wanted. There was no promise of poly ending, outside of a speculation.