What's your problem with out of wedlock marriage? Marriage doesn't automatically make a relationship more stable.
It does if it happens in a culture that supports marriage and recognizes its importance as a source of stability and resilience for families and their children.
This is one of those issues where large portions of the left frustrate me. There's such a preoccupation with leveling hierarchies and dismantling the social structures that support those hierarchies that the harm done by leaving no realistic or sustainable replacement that fulfills the same functions is ignored.
I don't know. Single parents are not good by any means especially in non welfare states, but is it inherently worse than the phenomena it replaced (i.e. shotgun marriages)? I think the former is probably worse than the latter in the US, but this isn't necessarily always true.
I think one can recognise family breakdown and divorce as a bad thing on a societal level without considering them immoral acts for an individual.