Absolutely Preposterous
First of all there is no comparison between cheating on your wife and her making you believe your daughter is about to be killed. The first is reprehensible, the second is sick and twisted. If she wanted to get revenge, she could have made her own porn video with some other guy and made him watch it. How many men would go through that and be standing there telling his wife everything was fine? He had as much reason to be outraged (more even) than she did.
This is the biggest howler of an ending you will ever see. It's beyond ridiculous and way beyond believable.