I get what you’re saying and I somewhat agree but at the beginning Euncheol refused to anything with him. Jonggu basically forced (couldn’t find a better word) him into complying, Jonggu was the one who wanted to play out Euncheol desires and fetishes so he had to know deep down at some point that he wouldn’t be seen as anything more than just a pet dog he wanted to make his master happy no matter what so if he’s happy with the other red head guy he should be happy too right? Let’s be honest he didn’t know when Jonggu would turn back into a dog and he realistically chose a better partner. Euncheol also, thought that Jonggu feelings weren’t romantic and he had never thought of Jonggu in that manner. But by now we all know how it’s going to end so yuh
Jonggu deserves more good things, Euncheol is a dipshit he still treats Jonggu as a complete dog but he never considered his human form having human feelings, he used Jonggu to get his fetishes just like playing with a dog. If only I have the ability to be a manhwa character I'll save Jonggu from Euncheol and love him so much ( ̄へ ̄)