I'm writing a novel where I imagined two or three subplots (or storylines). Now I found that one of the subplots has evolved and grown so big that It can be an independant plot itself and could (or could not) lead to another novel.
It's a bit annoying for me, because now I have to decide whether I have to separate this subplot from the first novel (removing a layer of narrative) to write another one (which actually would be a short-story) or just let it and use it to enrich my novel.
Any advice on what I should do to decide would be welcomed.