.. you sir insult me desu~ the only one I can think of is Inside the Cave of Obscenity but thats vere loose desu~
http://www.novelupdates.com/series-finder/?sf=1&gi=3,157&mgi=and&sort=abc&order=asc choose by yourself
Reverse Harem, if you are talking abt that. Someone pointed out. Inside the Cave of Obscenity. & if you want just POV. Then Shield Bro
『Shirayukihime to 7 Nin no Koibito』to iu 18 kin Otomege Heroin ni Tenseishiteshimatta Ore ga Zenryoku de Oujitachi kara Nigeru Hanashi
I remember reading the synopsis on the site that translate snow white and the 7 lovers, the mc and her brother reincarnated in an eroge and she doesn't want her brother to get an harem nor get her echi cgs lol There is also Escape Galge where the mc regains her memory and tries to destroy the ML harem
I admit getting curious if there is an author willing to write sth like that without making it P0rn, but the only entry in that list that is not a reverse harem is a no-male-allowed yuri story.
"Empress with no Virtue" & "to be a virtous wife", technically fit your bill. even though MC is the main wife of the Male Lead(ML), he have other women as concubine or consort.
Hmmm... Not quite what I am seeking. The main character is a harem member of a guy, and intend to make her as the one true girlfriend, or make it into a harem. Any destruction flag story naturally has harem, but as villain, they are not eligible. A member of harem who seeks to escape the harem is not what I seek, either.