The series description is quite inaccurate:
- Alice is not a princess. She's the "villainess" a prince was originally supposed to marry.
- The Prince cancels the engagement, not Alice.
- Alice wasn't engaged to Ex (the MC of this manga), she was engaged to the prince.
"The first prince abruptly ends his engagement to Alice Misty, a duke's daughter. Witnessing this, Ex Loss, the Knight Commander's son, has a sudden recollection of his past life. Transported into an otome game, he recognizes the unfolding events. Refusing to accept the wrongful blame placed on the innocent villainess, Alice, he resolves to protect and claim her. Reincarnated with a mission, Ex cherishes the villainess as his chosen path in this heartwarming tale of love and reincarnation.
"
Something like that would reflect the actual story better.