
ohhh yeah then after 10 years he became a whore that's amazing huh

Honestly, i think sex just became something else to him entirely. He mentions early on that he absolutely spiraled after Yeongwoon left. Some of his ex-partners have commented that he either objectifies them or is too much. Seeing as his brother is using this kiss as a means of control, my guess is that Seo-in as a twisted adult does something similar, where he uses sex like escapism or just physical relief. We see him mostly use tools on others so it might be his way of feeling in control.
I think the best way we can console ourselves is if we look back at that first time they had sex and Seo-in was clearly overwhelmed and surprised bc it was nothing like the sex he envisioned nor was used to. There was a clear difference from once feelings were involved.
Is the seme is womanizer?? And the mc is naive or dumb??