Spider-Man and Mary Jane Watson are a classic comics couple, but Stan Lee always intended for Peter Parker to end up with his "one true love," Gwen Stacy. While long-term plans changing in comics is nothing new, the idea that Stan Lee never imagined Peter and MJ as a couple might come as a shock to fans of both characters who've seen their ups and downs throughout the decades. The change in love interests can be attributed to different writers, the changing society of the 1960s, and the eventual bowing to peer pressure from the many Marvel Comics readers and fans of Spider-Man.
Gwendolyne Stacy first appeared in The Amazing Spider-Man #31, published in 1965, in a story called If This Be My Destiny. In it, Peter was introduced to Gwen in college. She took a liking to him immediately but her advances fell on deaf ears. Peter constantly gave Gwen (and everyone else) the cold shoulder. Aunt May was quite ill and Peter's mental health was in serious jeopardy, which led to him becoming erratic, irritable, and aloof. Stan Lee clearly intended the two characters to have a rocky beginning before becoming friends and eventually more - a classic start to a comics-based relationship.
Conversely, Mary Jane was introduced as a joke. As a running gag, Aunt May would constantly attempt to set up Peter with Mary Jane, who lived next door. Peter (and readers) assumed that anyone with Aunt May's seal of approval must be a boring, plain, behind-the-times character, but the now-famous panel from the end of Amazing Spider-Man #42 in 1966 showed Peter's shock when Mary Jane first revealed her face. "Face it, Tiger - you just hit the jackpot!" she says; Stan Lee didn't know it yet, but this moment was the beginning of the end for Peter and Gwen. In Stan Lee's original plan, Mary Jane was to serve as "the other woman" whom Peter would date for some time before realizing Gwen Stacy was the person with whom he wanted to spend the rest of his life. To facilitate the storyline, MJ was made a vivacious, trendy "mod girl" who stood in direct contrast to Gwen Stacy.
To a certain extent, the plan worked: Peter dated Mary Jane, the two eventually broke up after - again - complications with being Spider-Man got in the way of Peter's love life, and he began a relationship with Gwen Stacy. But despite the plans Lee had mapped out, fans still wanted more Mary Jane. The very character traits that made her interesting to Peter also made her interesting to the readers.
While The Death of Gwen Stacy wasn't written with the intention of bringing Peter and MJ back together (it was written because Gwen made Peter content and writers loathe a content Spider-man), it did eventually lead to their relationship rekindling after some time had passed. It must be noted that at the time of the story's publication, Lee had stepped back from actively writing Amazing Spider-Man books and had passed on the job to Gerry Conway. It was his decision to kill Gwen Stacy, something Lee never intended. "[Conway] killed Gwen Stacy! I didn't want to kill her. A few issues earlier, I had killed Gwen Stacy's father, and it looked like we had some sort of hatred for the Stacys, like we were out to destroy them, which of course was not the case," Lee said of the decision.
For his part, Conway despised Gwen Stacy, saying “[Gwen Stacy] was a nonentity, a pretty face. She brought nothing to the mix. It made no sense to me that Peter Parker would end up with a babe like that who had no problems. Only a damaged person would end up with a damaged guy like Peter Parker." Perhaps Conway is right - perhaps Mary-Jane's troubled past and Spider-Man's terrible mistakes mean the two are perfect for each other. Or perhaps Lee had more stories in his head for Peter and Gwen that would've moved both characters forward in their lives. Unfortunately, fans will never know.
Source: CBR