Gwen Stacy
According to Lee, who scripted all of the stories featuring Gwen Stacy up to this point, the original intent was for Gwen Stacy to be Spider-Man's central love interest. However, Mary Jane Watson's unexpected popularity with readers after her debut changed the course of the plan as fans liked Mary Jane more and demanded for her to be Peter Parker's main love interest instead, and that "no matter how we [i.e. Lee and his artist/co-plotter collaborators] wrote it, Mary Jane always seemed more interesting!"