I’m so confused about the thread, can the seme see the thread? Is he lying about not bei...

I think he cut the thread and put it on himself to take his luck/destiny.

I think rather he did that coz he was obsessed with him but the bad luck was a side effect

See but Im confused what does the thread represent? Like he can see it?

What does the thread represent though?

Connection? Like red string of fate maybe? And i think that the reason he was able to cut it was because of his relatives. I mean its easy to just get instruments that can cut and see the string or ask them to do it themselves since hes a spoiled child in the fam

I think for this manhwa it's treated as destiny. At least that's my current understanding and could change later. I also saw someone say that black is generally related to obsession in Korean culture (this could be wrong I just saw it on a different site). So from this I'm guessing MC's destiny (signified by the red part of the string) was supposed to lead completely away from ML but when ML cut the string and attached it to his own by force that turned the rest of the string black to signify the ML's own obsession with MC. I'm guessing ML wanted to be part of MC's destiny so badly that he made it happen. Unfortunately it looks like there's karmic retribution that ML is dealing with now (the bad luck).

Maybe it represents fate. The whole thing. Love , Career , Family , Good Luck. That man destroyed his whole life for his own 3rd grade obsession while he's having a time of his life.
Disgusting

Your explanation seems on point