They don’t have to stay with the person they started with, though. The whole point of the show is to explore different connections and see who you have the strongest connection with. KC explored in Casa and ended up finding someone else. It wasn’t “too late” because that’s literally what Casa is for.
@aftersunfilm the concept of Kenzie and Dylan (who aren’t compatible at all) being in the top 4 … you bird brain bitches have to stop voting based off liking someone.