I’m trying to find this manga where the girl finds out her sister was sleeping with her ...

I’m trying to find this manga where the girl finds out her sister was sleeping with her husband she also finds out he has been making her infertile. The sister I believe ends up pregnant and she seeks to divorce her husband she also meets and falls in love with the crown prince? But due to a prophecy where one of the sisters would marry the next king and bring happiness and glory they can’t be certain so the sister also ends up his concubine even tho he only loves the main character. Anyone help that’s all I remember! ┗( T﹏T )┛