What makes 'My stepmother's daughter is my ex' light novel interesting?
The light novel is interesting because it not only focuses on the romantic aspect of the former relationship but also on how the two characters now have to navigate their new family situation. They have to deal with living together under a new family structure while having a past romantic history. This leads to many internal and external conflicts that keep the story engaging. For example, they might struggle with how to act around each other in front of their new family members. Also, there are likely to be moments of jealousy or unresolved feelings from their past relationship that resurface, adding more layers to the story.
It's interesting because it challenges the norms of family and romantic relationships. We usually don't think about having an ex become part of our family in such a direct way. The light novel likely explores how the characters grow and change in this strange situation. It might also look at how society views such relationships and how the characters themselves come to terms with it all.