Such a comic is definitely not something positive or acceptable. It's likely filled with unethical and potentially harmful material related to family in an inappropriate way.
The main distinction of porn with a story genre from regular porn is the presence of a coherent narrative. Regular porn often jumps straight to the sexual action, while the story genre tries to add some kind of story framework around it. But in the end, both are adult-oriented and feature explicit sexual content.
The term for story porn can vary. Sometimes it's called 'sexual narrative' or 'pornographic literature'. It really depends on the context and who's using the term.
No, it's not appropriate. A family should be based on love, understanding, and mutual respect. Spanking is a form of violence, and in a marriage, it goes against the concept of a harmonious relationship. Couples should communicate through dialogue rather than using such improper means.
In many ways, they are different. Reading a porn story gives you more room for interpretation and imagination. Watching it, on the other hand, is more sensory and direct. But which is more impactful depends on the person's mindset and past experiences.