Backstabber

Backstabber: one who betrays a trust or an allegiance

"To my beloved husband, I wish I knew how to stop giving back the knife you used to stab me in the back the first time"

"The truth is the moment I met you, I knew it was always going to be you. I couldn't think about anything else"

"Betrayal never comes from your enemy"

"No one can hate you with more intensity than someone who used to love you."

Olympia the wife of Dark Knight.