
He moved in with him obviously so he could protect Donghyuk because Yule threatened him that if he didn't then "that" would happen again. If you read the raws by using google translate Kyungsoo isn't attracted to Yule the only reason he's with him is he has no money to find an apartment and actually acts cold towards Yule

Kyungsoo didn't say yes when Yule asked him if he regretted approaching him in the past. Kyungsoo also went and had sex with Yule while drunk. I know he moved in with Yule to protect Donghyuk at first, but little by little he's giving into Yule again. He didn't tell his sister he was in trouble when she asked him if he was ok. She even knows they have sex and that her brother does bad things to people he likes, so why not tell her and ask for help?

I forgot to mention if you read the raws she is also fucked up because Kyungsoo tells her I think about the situation (basically asking for help) and she tells him that he just has to endure it and that she will help him endure it because Yule is acting "normal" and it's because of Kyungsoo and she tells him does he forgive Yule, that their both in love and need to be together. That's her "help" she's not as kind or sane as we thought

Then it just means the translations are super bad, which doesn't really help me want to read this manhwa anymore. If they're going to leave such important things out, I don't know what the point is in me reading this since I'm not getting the full story anyway. But thanks for letting me know. Now I know this story isn't as bad as it looks like from the translations
I'd much rather go to the police instead of having to live like that. I'm so done with this manhwa because it looks like they might end up together. What Yul did is unforgivable no matter how you see it and he's totally messed up in the head but it looks like Kyungsu is going to give in and live with it because he's still attracted to him. So messed up