Well, 'ntr fiction' typically refers to stories that revolve around the concept of 'netorare' in Japanese. It can involve love triangles or situations where one character's relationship with another is interfered with in unexpected and often emotionally charged ways. It might show how characters deal with jealousy, betrayal, or unexpected changes in their romantic relationships. It's a rather niche genre in the world of fiction.
NTR manga typically involves a situation where a character's romantic partner is stolen or has an affair with someone else. It's a genre that can be quite controversial.
There is also 'The NTR World'. This novel stands out as it not only shows the ntr relationships but also delves deep into the psychological aspects of the characters. It makes the readers think about loyalty, love, and betrayal in different ways.
The 'Haruhi Suzumiya' series also has some elements that might be related to relationship exploration. The story is centered around Haruhi and her friends, and there are various interactions and relationship developments among the characters that could be considered in the context of complex relationship V novels.