Good lord. First of all, this is more than a stumble, this is a gradual decay that's been going on slowly for years. Second of all... You act like she's an ex-girlfriend that broke your heart. She's just a talking head on a screen, why did you put so much of yourself into her? Also, you must not have valued her that much, because you started to hate her the picosecond she disagreed with you.
Unironically, you sound like a cultist. This is how cultists treat people that betray the cult. This is how Scientologists treat people who they feel betray the church. They're "heatbreaking and evil" and they're suddenly the worst person in the world for the sin of disagreeing or going against the gospel of the cult.