Do you see there being a point in this? Some of these people live and sleep together and many have 3-6 children over the course of multiple years and then one day suddenly decide to get married to one another. Shouldn't the marriage have come first?
I guess the conventional way is getting married first then having kids. But at if you're at the point that you're referencing then I don't see the point of getting married. The two are married just without the paper saying so.