It should be told in a dual timeline progression where there are two starting points, one being their marriage, and the other being his time in prison. It can start with scenes from their marriage that he's narrating as he writes a letter to his wife from a jail cell asking for forgiveness (though not mentioning what he's done). From that point it moves forward through their marriage up to his arrest as well as from his writing the letter to their reconciliation.
You can have scenes where criminals kick the shit out of him for liking little kids and all the dark scare tactics taking place in prison, but the big reveal that he's covering for his son's mistake coming toward the end. Damn it you could make this so stealth that people would think they're watching a real drama, not Christian propaganda.