Isn't that up to them? I mean the Ukrainians? It's not as if the west is forcing them against their will to keep on fighting for their country and freedom.

In the first months of the war hundreds of thousands of Ukrainians returned to their country to sign up to fight. We either support them, or abandon them to their fate. I don't see how you can credibly claim that abandoning them, despite their appeals for support, is better for them and in their interests. It's clearly in the interests of the Russian government, but why should the west care about that?

Sending UN peace keepers is a nice idea, but unfortunately Russia is a permanent member of the UN security council, with a veto.