Looking for a manhwa

Not sure if it was just a promo or the prologue but basically rich noblewomen with light orange/orange hair is lovers with a black haired knight and implied sex. Then a saintess or some light haired/platinum blonde girl comes in and I don't know if it was after or before they completed their quest but knight breaks up with her and she's devasted but I think she goes back in time(?). It had a really moody art style with grey shadows and stuff.