Similar as in reverse harem or as in tragic/depressing?
Anyway, a few manhwas/novels that I found to be similar in both aspects are these:
https://www.mangago.zone/read-manga/the_secret_bedroom_of_a_dejected_royal_daughter/
https://www.mangago.zone/read-manga/the_fake_saint_waits_to_leave/
https://www.mangago.zone/read-manga/kill_my_husband/
(they're all more explicit though)
And this also has the same depressing vibes and is kinda reverse harem: https://www.mangago.zone/read-manga/kill_the_villainess/
If you mean one or the other I have some lists:
Actual harems with a FL: https://www.mangago.zone/home/mangalist/2375222/?filter=&page=1
Tragic/depressed mc: https://www.mangago.zone/home/mangalist/3101817/
Umm so... I really got invested of this story “One Husband is Enough”and i really want to find stories similar to this one but i can't find one, Can y'all recommend me some?? ╥﹏╥