While I definetely think Cena is a hard worker, I wouldn't put it past him to want some time off. The dude has been a workhorse for the WWE for years, not only has been involved in a major with all the wrestling events, but then there are movies, commercials, promotions, PR events etc, he has been doing all that for years. The wrestling schedule alone is enough to wear most people out(all the top talent work 4-5 times a week, and usually 2 matches on a night). So I could see if he was burned out -- it happens to everyone.
It is also fair to point that there is a possibility that most of what happens on the social media is just kayfabe, the WWE has realized(as most business have) that social media is a good tool.
As far as the divorce goes, Cena seems to be a stand-up guy, but I suspect there is also a possibility aside from his wife being a gold digger or the wrestling schedule taking the toll on their marriage that Cena was simply sleeping around. It happens more than one would think. I don't think it is likely, but still possible. When you are a celebrity, especially a good looking, highly paid and recognizable one, you will get gorgeous women throwing themselves at you on a regular basis. Which is one of the reasons, most celebrities probably shouldn't get married so hastily -- they really can't have normal lives for the most part.