Also, Europe is forced to support Ukraine in current situation no matter what they do at this point. They've already invested too much money and political capital in supporting Ukraine, they can't simply back-off from that into atmosphere (like Putin).
Not at all.
First of all, it's important to remember that "Europe" doesn't exist, as far as foreign policy go. What you have is 28 member states, with conflicting goals trying to kinda work together.
So basically, what happened was that there was very little appetite for further expansion in Western European countries, and certainly no appetite for getting Ukraine within the EU anytime soon. (Sure, Croatia got in, but they have a tenth of the population and 5 time the per capita GDP of Ukraine, so no one is worrying about hords of Croats getting our jobs). The Eastern Partnership, the deal whose refusal started the Maidan, was basically a compromise between Western Europeans and a bunch of Eastern Europeans and Nordic led by the Poles: not access to the EU, but a way to tie Ukraine to Europe.
That being said, Putin's reaction caught everyone off-guard. While the Western Europeans still by and large don't care much about Ukraine, it has scared some Eastern Europeans, including some like Estonia, who have sizable Russian-speaking population, are very vulnerable to Russia, fears it for historical reasons and have already suffered aggressive actions (The 2007 cyberattack come to mind).
So now, we again have several countries coming together. Some, like the Estonians, feel like they have to help the Ukrainians achieve the kind of independence from Russia they got in 1991 (For the anecdote, Estonian intelligence was of great help to Georgia in 2008, and the flat my father was working from was called the "Estonian kitchen" as a lot of intelligence agents worked from there). Other are scared, and feel that we have to stop Putin in Ukraine before he start chewing on them. Some like France or Britain don't care that much and mostly want to keep Russian cash from flowing in their shipyards and financial centers, but are pressured into enforcing sanctions by the other.
None of them feels like we need to support Ukraine because of the sunken cost fallacy.