This story is about the older brother, Jin-woo from Still, I Like You, and what happens after.

After a bad break up with his first love, Jinwoo falls into a creative slump with his ceramic art. During this slump he meets Colton, an alpha with whom he has a history. As things get steamy, it’s clear that they both have an agenda. And soon enough, the situation starts to get a whole lot more complicated. It was bound to, especially when pheromones are involved… As time goes on sex begins to have meaning.

Original Webtoon:
Lezhin, Bomtoon, MrBlue, Naver Series, BookCube

Official Translations:
English, French, Thai, German, Spanish, Japanese

Note: they're both alphas so they won't get matching marks but the author did post on twt what they would have looked like if they did:

AU with matcing marks: Damon and Colton