Idk if I should say this....
but I have a feeling that SH has been avoid being close with JS in front public eyes. You can only caught some of their moment BTS ( bedscene and YB wrap-up party)
Remmember the last concert, the whole cast was taken photo together and with fans as well, SH tend to stand/ go around YH and HK but not JS
In the BTS, SH was fooling around with HK and talk to YH a lot when they have spare time...
I think she know what viewers thinks and try to avoid it even if they are really close and comfortable around each other
Let's take a step back and review what had happened....
They were close and not afraid to show their passion to the other on-cam until YB ended (interviews, bts, talks, photos...)
They MCed together and still had so much fun in front of public eyes.
JS talk about his mom and the how they was a match twice ... but didn't choose her at the Champaign
People talked about wedding plans... and SH and her manager saw them 
SH posted ... sad ,loved songs in her play list;( ( that she wants to end it and not want to get hurt ...)
SH mced with YH and HC, and performed with LSG in "WYMM"
and everything HAS CHANGED here

JS acted cold toward SH at the Drama Award ( not even look at her properly and give her a hug for congratulation/ SH didn't went in to congrat JS as well). Ok, I know there was a rumor that they hug but why didn't they record it or taking any pic? -->no evidence after all

They don't even seat next or talk much to each other at CNBlue Debut and yet claimed each other good friends not quite long ago

This is just suspicious( funny and sad at the same time^^)...

I know a lot of people think SH like JG ( not that I oppose it) but I think JS like SH more with all the teasing, flirting and telling others about his mom likes her...
SH is naturally sweet and very comfortable with her co-stars ( as you can see she was close with YH and HK as well Uee, Lee Wan...)

But when JS talk about their relationship in public ( and this is so in his character: straight-forward and open-minded...) which may has caused some scandal and may affect their images ( of a girl especially) ( and also gained an amount of antis as I read somewhere)... so I think they had to talk it over and decided to keep their interaction low ... which is sad for fans... Yet it's a good way to maintain their close relationship since they are so young.
I will wait and look forward to their future...
Both of them are still very young and have a lot of potential... and I hope they will keep their close relationship ( romatic or not) forever!!!! :cheer: :cheer: :cheer:
and if they will have another chance to re-pair, I will jump out of joy

.... just love their chemistry<3