Well, I caved in and found the novel (google it, there are links on novel updates) ch73 is about ch20 in the novel, yes I was shocked too. There are 33 chapters total. I don’t often see such short k-yaoi novels and I don’t know how the Manhwa turned 20 chapters into 73, but it’s so good the Manhwa is tagged shounen ai, but the novel has multiple explicit scenes.
This part below might bother some readers:
The ML is a bit… intense. He manipulates the surroundings to make the MC stay with him, but it’s not like MC didn’t want to, because of his experience with his dad’s abandonment he was scared to go all in in a relationship so it doesn’t bother me that much. ML being a bit stalkerish did tho ( ̄∇ ̄") its not like he even hides his personality that much, several times MC feels like something is wrong, but is a bit of an idiot so he doesn’t really get it and drops his suspicions quickly.
But besides the ML’s creepy side, which I honestly didn’t expect, I do love the novel.
Sorry for the late reply.
So spoilers…
MC realizes he fell for the ML on his own but can only see himself as a bottom so he hesitates at first. But they don’t really fight their attraction and he comes to like it. The problem is, he acts like he’s waiting for the relationship to end, he doesn’t want to be all in since he’d been abandoned by his dad before, so the ML does some manipulation. He makes the MC think he’ll be hurt if the MC breaks promises, but is good luck as long as he’s around to trick MC into staying with him. MC comes to believe he’ll give ML good luck as long as he stays with him so they get officially together. ML had even distanced himself from MC, he did it all to make MC come to depend on him and want to be with him more than he feared being abandoned.
Also, he has CCTV installed at MC’s place and basically watches him ( ̄∇ ̄") and purchases a building close to his office, anyway he keeps a close eye on MC, and when it seems like the MC is trying to back away from him, he gets angry. But since the MC is pretty slow it never actually leads to a fight. He fixes the problems of MC’s coworkers and gets his friends in relationships to reduce “competition.” He also mentions once if the MC cheats he’d track him down and harm the other guy? And multiple times insinuates MC can never leave him (like he’d do something to him if he tried) and MC does notice the intensity but then completely misses it.
And one thing about his relationship with the ex. Actually, he knew his teammate liked Andy and deliberately got into a relationship with him (idk if it was to get back at the teammate for being rude or something) he knew they were into each other and still acted like the victim when they got together (like acting surprised when he caught them together even though he knew). I can’t explain it well, you’d have to read it to truly understand. Hopefully the manga won’t shy away from how dark he can be.

I’ve been letting this marinate for the entire year and you’re telling me it was on hiatus the entire time??? No wonder I thought the updated chapters were so few