Recs for side couples

Basically, I’m not sure how to call this syndrome but I always love side couples more than main couples. If I read a long manhwa/manga and there is no side couple I feel like something is missing.

I’m down for any genre or relationship dynamic as long as there is a good balance better main and side couple. Preferably if the latter have their own season (e.g. All About Lust), sequel (e.g. Window to Window and Room to Room), side stories (e.g. Stranger then Friends) or just share main story time with the main couple (e.d. Fate makes no mistakes and 19 days).

I recently finished Killer Crush and while I love the main couple so much I hate that we didn’t have any side stories with the crazy blond kid and the boss.