As there is a socially (and legally!) defined concept of marriage, judging is inherent in that. Whether one advocates a looser or stricter definition is based on many subjective factors. How or whether we judge others for not abiding social norms or our own personal values is a separate and related matter with no obvious resolution.
Handman is right that most people, including those taking a very pro- view of marriage as an institution, are understanding when marriages don’t work out.