Nobody knows what will happen in Ukraine. The future is always unknowable. Ignore people who say they know. Including me.

"From a military standpoint, the costs to Russia have been far higher than would be the case without such assistance from the West. It’s possible to speculate on what might push the war in various directions. But so far the ‘speculators’ have been generally wrong. No Russian Blitzkrieg. No Russian collapse. No striking results from unprecedented sanctions. It’s best to admit that there are a range of possibilities and try to think through how we would deal with each, as opposed to attempting to predict what happens next.” 

A former Pentagon official quoted in the Times today.

The same article says American spies think Putin will continue the war for years if necessary. Obviously the war will end and Crimea will not return to the Ukraine. 

No peace is possible while either side doesn't want one, but I hope a durable peace comes soon, before Ukraine is destroyed.