First, you need to realize Russia leased Crimea from Ukraine and lived there like I live in my rental house. Russia can't invade a place it already lives in, and the lease doesn't end until 2042.

Second, you need to understand Eastern Ukraine's attitude toward the West and Russia. Ukraine's political and economical aspirations are similar to the US during the Civil War.

Third, you need to understand the West's interest in the region and propaganda is universal.

There isn't a good guy, and we're all lied to all the time. We tend to side with the West but we shouldn't side with any government. Globally, the people don't win wars or benefit from our dumb governments support for the wealthy.

https://www.theguardian.com/world/2010/apr/21/ukraine-black-sea-fleet-russia