Nextmovie spoke with the director of David Slade & learned that they considered having Bella & Edward's wedding at the end of the Eclipse movie.

“We discussed a lot of the things at the script-writing stage — at one point, we were even going to shoot the wedding at the end of ["Eclipse"] but we knew there was another film coming,” Slade tells NextMovie exclusively.

“We knew that a lot of that could go into the next film. And we just made the most concise version of this story that we could.”

Source

It's probably a really good thing they scrapped that idea. I know I would have been ticked & I'm sure a lot of other fans would have been too.