From NOIR:
A rich, spoiled, successful, handsome man finds himself looking for something new in his life. Taking advice from his past lover, he seeks a roomate, an "easy relationship". However, instead of a glamorous, sexy, cute female... a MALE mistakenly shows up at his door..? (In full color)

Lezhin Web Publication

Seung Hun is a handsome playboy who's never experienced true love. Woo Sun is a charming playgirl who wants to be loved for herself and not her beauty.

Jong Yi is the beautiful, mysteriously childlike and vacant boy who becomes the object of their affections. A complex love triangle evolves between these three, further complicated by the involvement of Jong Yi's unfailingly devoted childhood friend and first love, a girl named Yu Ri.

They're all soon to discover that love is a long, painful path...especially if the object of it is completely oblivious to your attentions!

Note: As indicated by the genre tags, there are both shounen-ai and romance pairings in this story. It is not F/M romance only.