This one is really hard to answer because so much happened because of Kikyo's death. Not only the Inuyasha/Kagome/Kikyo love triangle would have been affected. If they had completed the jewel with Kikyo still alive, would she have been the one trapped in the darkness? It's hard to say, but if somehow Kagome was still sent back beyond the well and Kikyo remained with Inuyasha, wouldn't she be happy that he was happy even if they were separated? Sad to say, but Inuyasha has always shown favoritism for Kikyo throughout the series, yet he also shares a close bond with Kagome, making them equals. I've also found myself wandering this question, but in the end, it was for the best that Kikyo finally be put to rest and for Inuyasha and Kagome to live happily. After all, Kagome is Kikyo, they share the same soul despite their opposite personalities so in a way, Kikyo did get to live happily with Inuyasha, just in a different life.