If the Fate says that they will never be together, They couldn't do anything... because is his fate... and nobody can change it... 

"Maybe We have to let it be" Kevin said to himself with tears rolling over his face, no matter how much He loved Him, KiBum would leave him soon after all, and He couldn't do anything to avoid it...  Kevin raised his face trying to remove his tears with his hands... Maybe He has to let go his KiBum after all...