I'll believe this when it happens. Numerous wrestlers say that they're going to retire and they just about never do. Booker T said he was going to retire back in 2004, but it was just last year that he was trying to get another deal with WWE after TNA decided they no longer wanted him in late '09. Ric Flair supposedly retired until he decided a shitty tour with Hulk Hogan across here with enough incentive to get into the ring. Even Kane, a guy who I honestly believed, said he was going to retire years ago, and yet he was world champion just a month ago. These guys are very emotionally attached to pro wrestling, so while he may think he'll be leaving WWE now, when the time comes that his contract is running out, he may be thinking different.
And yes, I know I've taken "leaving WWE" and turned it into retirement talk, because I honestly can't see Edge leaving for TNA. While their schedule may be attractive, he's often been WWE's go to guy for years now. I doubt he'd want to trade that in for life in TNA, where he'll only be the big star until they sign someone new from WWE.