I write screenplays, too, and MeeraReed is absolutely right in saying there is no story without a conflict. Those stories that are all about a person choosing between one or another person would fall flat at the climax if the protagonist chose both. The audience would say, "After all that struggle, she/he doesn't even pick one? How lame! I watched that journey for nothing!" They would feel cheated because they would be rooting for one of them, and feel like it's unfair if there isn't a clear winner. They also need a character to identify with, whether it's the winner or the loser. So, love stories with "happy poly endings" would have to center the conflict around some issue other than the typical two people trying to win someone's heart. But my choice would probably have an ambiguous ending where it looks like more than one person wins, but you're not sure, so the audience goes home and can't stop talking about it - "Who do you think she marries? No, really?! I thought..." That kind of thing.
Last edited by nycindie; 02-01-2012 at 05:12 AM.