He can't be happy here as he starts to realise how hopeless it is under Wenger but I don't really see where he can go. It's his last contract and money will be the priority, unless he wants to go to China who can offer him serious wages aside from us? Can Juve, I guess, especially if Dybala leaves? Bayern won't be in for him...I guess one of Chelsea, United, or City could get involved but given our strong financial position we won't sell and he'd have to run down his contract.
Think the most likely situation is we eventually cave in to his demands and he re-signs. Hopefully he's not a big fan of Wenger, though, and can be a force to getting him out this summer. Doubt it though.
edit: forgot about PSG. That could make sense, especially if Di María leaves.