Ever Night (season 1) - ML and FL are very close with each other since childhood (in fact form sth like surrogate family) and the ML honestly falls for another girl ( who is a sympathetic character , suits him too and reciprocates his feelings). All the characters are pretty young, inexperienced and only learning their own emotions while growing up and maturing. The triangle here is not about who is better but about recognizing which feelings and connections run deeper.
Handsome Sibilings - with that one I have problem with saying who is ML , SML , FL, SFL though. There are 4 characters also one girl gets a bit more screentime and comes earlier in the game ( let's call her FL) . So FL def fancies ML, ML maybe fancies her a bit ( or maybe not that much, probably it's unclear even for him;)) but he doesn't want any romantic entanglements. Later on he falls for another girl ( and FL moves on with other guy)