Peter Parker's doting Aunt May attempted on several occasions to romantically introduce him to her neighbor Anna Watson's niece. Convinced that his aunt's desperation in playing matchmaker was evidence that the girl must be homely, Peter avoided meeting her.
By the time Peter met her, he was romantically interested in Gwen Stacy, while Mary Jane dated Peter's best friend Harry Osborn, the son of Norman Osborn. After Gwen's death at the hands of the Green Goblin, and Mary Jane and Harry's relationship ending before his drug problems became evident, Peter and Mary Jane became a regular couple. Peter eventually proposed marriage to Mary Jane, but she declined and went to live with her family in Florida. While she was away Peter dated several women including Felicia Hardy (Black Cat).
When Mary Jane returned, she and Peter grew close and eventually she revealed her knowledge of Peter's secret identity. She had known for sometime because she had witnessed Spider-Man jumping from Peter's bedroom window while at her Aunt Anna's house in an adjacent upstairs bedroom. Knowing Peter's greatest secret Mary Jane opened up and told him of her dysfunctional family-life and how her party-girl attitude was a mask to cover her pain. The two grew closer and in time would become husband and wife.
Although Peter's obligations as Spider-Man have occasionally caused stains in the couple's relationship, they have persevered and ultimately remained together through times both good and bad.
After the Civil War, Peter is forced to decide whether he will accept Mephisto's offer to save Aunt May in return for wiping the knowledge and memory of Peter and MJ's life together as husband and wife from the face of reality, which would leave only a single, subconscious piece of their souls to remember, allowing Mephisto to feast on the pain exhibited by those vestiges for eternity. MJ accepts Mephisto's offer, but only with the caveat that Mephisto promises to restore Spider-Man's secret identity which he agreed to do without question. She also asks to put his life back as it was and have a chance at happiness. Mephisto accepts these terms, and in the revised timeline, MJ and Peter were never married (although they nearly did), but instead "dated seriously for years".
Current Version:
Mary Jane Watson (Jackpot Bracelet)
Past Version:
Mary Jane Watson-Parker (Pre-One Moment in Time)
Mary Jane Watson (Post-One Moment in Time)
Mary Jane Watson (Stark Industries)
