No, in a healthy relationship, such a situation is not common. Partners should respect each other's views and not force one another to accept untrue things.
It could imply that the husband is making his wife accept or believe in untrue or fabricated stories without her real consent. Maybe he's using some form of coercion or pressure in their relationship to get her to go along with certain narratives.
She can reach out to local women's shelters or support groups. These organizations are equipped to handle such situations and can provide resources like legal advice and counseling. For example, they can help her understand her rights in the relationship and guide her on how to protect herself legally. In many areas, there are laws against domestic abuse and coercion, and these groups can assist in navigating through the legal processes.
Granny teaching little girls such things is extremely inappropriate. It goes against all notions of proper upbringing and protection of children's innocence. Such stories are morally repugnant and should never be entertained.
No, it's not a common situation at all. In normal relationships, such a dynamic where a wife forces her husband to watch a story in the context of 'cuckold' (which is related to infidelity) is quite abnormal and would likely indicate some serious issues in the relationship.
Once there was a wife who was really into fashion and theater. She had always dreamed of seeing her husband in a different style. One day, she found a beautiful vintage dress at a thrift store. She convinced her husband to try it on for fun at first. She said it would be a unique experience and a great photo opportunity. Her husband was hesitant but finally agreed. He put on the dress, and although he felt a bit awkward at first, they ended up having a great laugh and took some really interesting pictures together.