I actually don’t know a huge amount about this guy and nobody needs to hear my musings but here goes:
* seems to have had previous experience of ED and bipolar disorder. Strictly, I would imagine, could have easily triggered the former and as another poster said, the endorphins, the undivided attention of Amy, the glitz and glamour could have given him a high and this is the unfortunate crashing low.
* I genuinely believe he thought the glitterball was his. If you have an ego that big (to think you’ve got it in the bag before you’ve laced up your dance shoes) then it could take a lot of time to do a “post mortem” of what went wrong and mentally apportion blame which then in turn could lead to resentment. (Someone had said he’d retweeted posts around the time of his couple’s choice that said the Judges had got it wrong/undermarked him etc).
* he could be looking for attention. He didn’t foresee his exit from Strictly and couldn’t do the tour however Giovanna seems to have done well in this play and coupled with the fact she won her reality show, he’s possibly spat the dummy out.
* he knows people will be talking about him being off social media. Not only was Gio’s play successful (I think?), his sister has split up with her boyfriend - maybe he’s not happy when there’s no attention on him?
Who knows, but whatever is going on, I wish him well.