Princess Ovelia, Final Fantasy Tactics. Her husband spends the whole game backstabbing and "Just as Keikaku-ing" the entire kingdom and screwing everyone including his best friend (the main character) over into oblivion. Then marries her to become king.
In the final scene of the game, she can't stand his bullshit anymore and stabs him as he is bringing her a rose bouquet.
For bonus angst points, her husband actually seemed to love her for real.