And for the umpteenth time it belongs in the realm of religion, NOT the state.
And, as ever, what the libertarian refuses to comprehend is that the expansion of the state was created not by some liberal conspiracy, but by civil society asking it to do what clan, church, and tradition no longer can because we no longer live in closed worlds. The fewer traditions you have, the weaker the "code of conduct", the more laws you have to have.
Let's see if we can help you understand this. Let's take for instance laws against stalking. It was not possible to stalk a pre-liberated woman because there was no way past a phalanx of chaperones and her male kinsmen. But once women are liberated and on their own, without their male kinsmen controlling their lives, the downside to their freedom is that that bodyguard of male kinsmen to protect them from bad men is no longer there. So single women look to the state and sexual harrassment laws to afford them patriarchal protections but without Father running their lives.
You ramble about "holding people responsible for their actions", ignoring the fact that civil society asks the law to do this because it no longer can do so through ostracism, excommunication, duelling, or fear of "what the neighbors will say". You flatly ignore the vital cultural role of naked coercion (no society has ever rested on airy, sentimental appeals to "personal responsibility") in controlling anti-social behavior. Marriage has always been backed up by coercion and always will be because it is that important to society, so rambling about how it is purely a matter of religion ignores post-Pleistocene human cultural development. So it is ridiculous to talk about "taking government out of the marriage business".