It could end with the husband realizing his mistakes and apologizing to the wife. After getting the 'crampie' from whatever she did, he understands that his actions have led to her taking such revenge.
Well, it could be that the wife discovers her partner has been unfaithful. So she decides to play a prank on him at a party. She might make him eat something really spicy that gives him a 'crampie' - like a stomach cramp. It's her way of getting back at him for his bad behavior in a rather mischievous way.
The story could end with a bit of chaos at first. For example, if it's a surprise pregnancy, there might be a scramble to get everything ready for the baby. But then, as time passes, they adapt and end up in a really positive place, with the wife feeling fulfilled and the family stronger than ever. In the case of a pet breeding surprise, they might initially be worried about finding homes for the puppies or kittens, but then manage to do so successfully and feel great about it.
One story could be that the husband found out his wife was cheating. Instead of getting violent, he quietly gathered evidence. Then he exposed her affair to their families and friends, which led to her being ostracized in their social circle.
It would probably end with the boy feeling better, his pain or discomfort gone.
She could end up in jail. Drugging someone is a serious crime, and she would have to face the legal consequences.
It could end with the two couples realizing that they are better off with their original partners. They've had their little adventure, but they've also seen that their own relationships have unique qualities that they value.
The story could end with the hubby rejecting the whole 'sissy' transformation. He tells his wife that he values his masculinity and while he understands her desires, he wants to stay true to himself. However, they still find a way to respect each other's views and continue their relationship, but with the hubby maintaining his more traditional male identity.
Morally, it is completely unacceptable. Nudity is a very private matter, and a wife should be loyal and respectful to her husband. Doing such a thing for a friend violates the boundaries of marriage and basic moral decency.
The wife might be shocked at first. If she has a more conservative nature, she could be embarrassed and quickly try to cover her husband up. But if she is more open - minded, she might laugh it off as a silly incident.
His character could become darker. The once - cheerful and optimistic Naruto might turn cynical. He would start to question all the values he was taught about loyalty and friendship. For example, he might see his past friendships as a form of manipulation by the village. This new - found bitterness would be a major shift in his character.