There's no pressure from NATO to fight. Ukraine is the one pressuring the rest of the world to help. Ukrainians don't want to give in to Russia (especially after the war crimes committed in occupied cities). And the military situation is not what it looked like right before the war. Of course, Russia has massive manpower, but at this point it cannot take over all of Ukraine, and there's a real possibility Ukraine will win. I highly recommend Institute for the Study of War's newsletter to follow the military situation: https://understandingwar.org/