Spidey joining the Avengers was the beginning of the end.
1-Spidey gets organic webbing, and joins the New Avengers.
2- Peter moves into Avengers tower, with his family in tow, and everyone living there automatically knows his identity. Totally out of character. Even the Torch didn't get to learn his identity until after that.
3- The Other occurs....worst storyline EVER.
4- Due to Peter's death and resurrection, Tony "gives" Peter a more advanced costume...consisting of Iron Man's colors, and makes Peter his sidekick.
5- Peter is played like a fiddle by Tony during the Titanium Man incident.
6- Peter loses his freakin' mind and unmasks on live television in fron of the entire world.
7- Peter goes against Cap.
8- Peter finds out that Tony, who has Thor clones and alterior motives behind every action, has been monitoring him via the Sidekick-Suit, due to Tony's knowledge of Peter's Spider-Sense.
9- Aunt May and Mary Jane are now dead women walking, as 2/3 of the 616 villians hate Spidey for some reason, and will inevitably kill them.
10- Peter will learn that he should have acted more responsibly and withheld his identity until the bitter end.....something he knew beyond a shadow of a doubt 44 freakin' years ago.
It's like a snowball that causes an avalanche.