For a while, Spider-Man in the comics was going through actual character growth. Peter Parker got married, started working as a teacher in the Bronx, made the decision to publicly announce his secret identity. Then made a deal with the devil to undo all of that just to reset Spider-Man to the exact same guy he was 50 years ago. I think because one of the writers wanted him to have a one-night stand and they definitely couldn't have him do that while he was married to Mary Jane. So instead, they just magically re-wrote history so that he never actually married her. Waaa.