10 Things Marvel Wants You To Forget About Green Goblin
2. He Had An Affair With Gwen Stacy
This... this is where things just get weird.
So, as most fans will probably have gathered already, the Night Gwen Stacy died is a formidable and influential Spider-Man story. Going back and fiddling with it in any particular way isn't really the best idea - but that didn't stop Marvel from doing so in 2004 with the release of the Sins Past storyline, which went back and retconned the build up to the story by revealing that Gwen and Norman had an affair, which led to the birth of two children.
No, really. This actually happened.
It turns out that Norman and Gwen had a one-night stand a couple of years before her death. She gave birth to twins during that time, managed to keep that a secret from all her friends and Peter - save for MJ - and used them as leverage to make sure Norman took care of Harry during his illness, thus adding further motive for Osborn to kill her during the aforementioned story.
MJ keeps this a secret from Peter until Gwen's children literally come back to murder who they think is their real father. The cherry on top is that readers are also shown Gwen and Norman's night together, and it just isn't all that pleasant.