Let me present you an alternative. Europe can build up a credible defense capability which will provide a strong deterrence to Russia. In that case you don't have to die in the trenches and you don't have to spend your life running away from the aggressor.
Nazi Germany did not invade Switzerland, USSR did not invade Finland (after suffering horrible losses in the Winter war), even though both had their own claims on them, because the costs of such an adventure were considered too high. A big part of this deterrence was a population willing to fight to defend their homeland.
> Nazi Germany did not invade Switzerland, USSR did not invade Finland
To be fair these aren't exactly the most relevant examples. On paper the balance of power economically (and military to a somewhat lesser degree) is certainly on the side of the EU/NATO. It would be relative pretty cheap to invest enough just to deter a second rate country (besides nukes) like Russia.
Nazi Germany did not invade Switzerland, USSR did not invade Finland (after suffering horrible losses in the Winter war), even though both had their own claims on them, because the costs of such an adventure were considered too high. A big part of this deterrence was a population willing to fight to defend their homeland.