Lord knows people can't figure out who to marry or when to split up on their own either. Government need not be involved in most personal matters.
You stumbled into a truth. People marry for a myraid of reasons. Few of them are suficient. Fewer still are reasonable. Place known consequences in front of them & the liklihood of ill-advised marruages declines. People are more apt to pay attention up front when they know they will be hurt later (as is the entire thought process behind laws) if they choose wrong.
You might know how to raise your kids but obviously many parents don't. People marry, have kids, start families, etc that are ill prepared for any of it.
Make them liable for their actions. Down with no-contest divorces. Don't allow stupid crap like dual-custody. Nobody knows how to raise their kids. It's learn-as-you-go. The ultimate on the job training. If you had both parents while growing up, under one roof, you're more likely to get it right. The more divorces & custom families we have, the greater the odds of fucking it up since there is no baseline.