In general, they want to protect their interests. As we see in Ukraine. Ive edited this article to focus first in giving my insights on the big picture regarding your question.
What we see is short and medium term thinking of both the West Europa and the Russian governments, from Tsars to current rulers. This is partly based on a history of mutual invasions and other rivalry.
So, from the Western perspective, I think we should reckognize the Russian feelings and rights, based on historical reasons.
On the other side, the memory of Soviet rule in Eastern Europe. As for now, the expansion of NATO to the east was a fundamental mistake and a very insensitive move. It stirred old nerves and wounds. Same applies to Russian expansion towards former Warschaupact nations.
Besides the old, the new reality of the global politics is mutual increased economic dependency. Money as the new superweapon to assure mutual assured destruction. This limits military ambitions.
Still, we cannot ignore the classic military strategic considerations of the involved parties. Those are partly outdated, but still the justified concerns needs to be acknowledged and adressed.
I hope this helps you a bit. Some toughts about the present.
In the overall wisdom, I see the need for a Eastern-European Military alliance, combined with the freedom to make trade agreements with both the West and East, for fundamental improvements of the present and future regional power balance and economic development.
I see some wisdom in a strong buffer alliance, in the military perspective. Note: while increased mixing is obvious, NATO is still a military treaty, compared with the EU founded for economical reasons. For the coming decades, we need stabilization in the centre between West and East, for the benefit of all.
A defensive military cooperation between Finland, Ukrain and Turkey can be good starting point for discussion: those nations have their own assets to contribute to such alliance.
Other nations like Poland, the Baltic states and even Belorussia might consider participation. This treaty will pose an independent power between Western and Russian interests.
This would be a good construction for the coming decades but might be retired within a century, creating new stability that will fundamentally improve into a endurable trust between neighbouring powers and the involved participants. New economic ventures, created by more security, can create a new reality, bringing prosperity for the region and geopolitical stabilty.