When Taken at the Flood

Who knows how often our lives might go one way or the other based on the smallest and most random chances? Or, as Shakespeare put it, "there is a tide in the affairs of men, which when taken at the flood leads to fortune." This is a choose-your-ending story, rather than a traditional series. You can decide which couple sees fortune smile on them as they pursue their unholy hate-bet. Or you may decide you want to explore both endings...