Pete and Mary Jane got married in Amazing Spider-Man annual #21, which went on sale on June 9, 1987. Jim Shooter did the plot, Jim Salicrup wrote it, and Paul Ryan drew it.
Then, JMS and Joe Quesada undid it, via a Mephisto spell.
Then, Dan Slott re-did it as part of the recent Secret Wars.
And apparently it’s all canon.