Title: Love is an Illusion! - The Queen
Seung-ah has been tied to alpha Do-gyeom, one of his best friends and first love, for twenty years, all by choice, initially as her friend but ultimately as her secretary. Unfortunately, this has given Seung-ah a front-row seat to all of Do-gyeom's sexual conquests and escapades. Seung-ah does his best to keep his longing for Do-gyeom under wraps. His only comfort is that Do-gyeom has no intention of getting into a relationship or marrying, meaning he can always be the closest one to Do-gyeom, even when he feels he has no right to be.
He's pretty content with this arrangement until Do-gyeom, after seeing her brothers getting married and starting families, decides that she wants to start her own family, too. Suddenly, it's not enough that Seung-ah has to chase away one-night stands; now, he has to chase away the one-night stands and try to find her a worthy spouse. To his surprise, that person manifests in an unrelenting female omega, an employee of Do-gyeom, and a one-night stand. Seung-ah was willing to give Do-gyeom over to a worthy omega of the same class and power, but this was just too much for him to bear.
Unable to see his long unrequited love get married to someone beneath her, who isn't Seung-ah himself, he runs to their longtime friend Mujin, who is happy to comfort Seung-ah in any way he can.