Something happens to the female lead and the male and female leads are together. The second male lead loves the female lead so he manipulates the female lead into believing that it was the fault of the male lead. So she turns on the male lead and sides with the second male lead, but rejects his love. Eventually though she finds out the deception and tries to win the male lead back who sorta hates her for awhile. Then he gives in to his love for her and they get back together.
Doesn't have to be historical or fantasy
Male/second male don't have to be related