
Jooin should just have his fun with them both & then dump them both.
Nothing good can come off Dating sunbae - he's just stubborn to own his property which he believes is Jooin
Cain is too obsessed, he doesn't have healthy boundaries with Jooin
If I had to choose though, I'd probably choose Cain. He at least chooses to wait for Jooin's consent.

I feel for chungwoo and Ho-in.
I can this getting exponentially dramatic in the next few chapters.
Chungwoo is struggling between trying to feel love from scumbag taesoo but not getting any while distracting himself using a boi who knows who likes him but almost feels guilty for indulging him
Ho-in on the other hand can't help but settle for pieces of chungwoo cause something is better than nothing. I can't tell you the number of times I've been here. I hope ho-in realises his self worth and stops choosing pieces of chungwoo and chooses himself instead, only then will chungwoo also be challenged to truly think about what he wants.
The MMS guys have already warned several times that they'll drop this if it continues to be uploaded here.
Just read it via their website - https://midnightmess.org/allseries/the-third-ending/
Also don't be a fool and tweet the author about this - afterall the manhwa hasn't been translated officially.