Putin has made the biggest mistake of his life - in expecting a short war or none, as per Crimea, has not anticipated the response from the USA, Europe, and the world in general (as to sanctions and support), and has misjudged the feelings of the majority of Ukrainians - allegiance to their democracy and as to fighting back. Plus he seems to have miscalculated the affinity of so many Russians with those Ukrainians who might be family or friends - hence why he has to shut down the media (even more) so as to prevent trouble at home. He is in the wrong and probably knows it, and despite all his rhetoric probably realises his big mistake and yearns for a solution that won't lose him face.
An old speech writer for Putin was on the radio last night and saying much the same (alluding to trophies for Putin rather than losing face), and I would tend to trust someone like this who would likely know Putin much better than most. Also, although the Chinese have denied such, it has been proposed that the Chinese leader insisted that Putin wait until the Olympic games were over before attacking, and this might account for the slow progress seemingly made as to a takeover - using too much weaponry and other issues, for example, during these 'exercises' or preparation for invasion as they will now be known. And hence why he had to keep on saying, 'we will not invade', although his definition of 'invade' might also be the issue - just a policing action, but involving the whole country (and regime change of course).
Of course, like most, I have no idea how this will end.