Recently, I found a lot of their intimacy. Daebak, they just need to speak up about their relationship. I'm sure that Running Man fans will not leave them if Spartace open their real relationship (I hope so).
Here are some evidences.
Here's the video when KJK and SJH were holding hand when they went to SBS Entertainment Award 2015.
source: spartacecouple instagram
Here is the videos when KJK and SJH side hug.