stay safe, play responsibly. http://iweb11.mangapicgallery.com/r/newpiclink/the_villiainess_is_adored_by_the_crown_prince_of_the_neighboring_kingdom/8/c8858a12d83f4c9d76c37f6671befc2f.jpeg
(the seal looks like a condom at a glance)
I think the hyung was not caring, and dismissive of another's feelings/situation. or that happened to him.
Hence he now reacts so extremely to another feeling hurt etc.
he is either trying to break what happened to him. or atone for how he treated another in the past.
The feelings of regret and guilt could be why he self harmed. (last 2 chapters i noticed hyung has self harmed)
It's not right for the seme to reveal his best friends (supposed) interest for the uke.
I reckon story wise it will be fine, but that's a dick move.