No, not that. Those are the negative consequences of not properly recognizing marriage as a lifelong covenant with rare instances of divorce.
The negative consequences are the fact that man and woman will not be recognized as one. Divorce will be difficult to deal with. Shared assets will be difficult to deal with. With marriage law, in cases of divorce assets can be split up properly. Those are just the most practical implications of not protecting the lifelong covenant between man and woman.
I’m pretty sure we had out-of-wedlock children before divorce was common. It was societal pressure as “not acceptable” that kept it to a minimum, not the legal difficulty of obtaining a divorce.
I lived in Chile in the early 2000s - divorce was illegal at that time. Yet there were still plenty of single-parent households where a child was conceived out of wedlock. It happened anyway.
As far as assets, I think it’s simple - register names, like on cars. If one name is listed, then it’s owned by that individual. If two names are listed, they jointly own it 50/50 unless other documented ratios are presented. For household goods - well, just like roommates divvying up stuff, it can get messy - but any severance of a relationship is messy, and not just from a financial standpoint.
I’m just looking at the pragmatic reality of today - Government recognition of marriage is NOT preventing the societal ills that marriage is supposed to prevent, and is in fact leading to a path of greater acceptance and legalization of the gay agenda. So do away with Government-recognized marriage altogether. Allow civil contracts between any consenting parties and be done with it.