The issue, IMHO, is not some inherent "right to have sex", but rather one of the extent to which the state should be allowed to intrude upon people's private affairs for the purpose of enforcing its laws, especially in cases where there is no complainant.
If a state legislature decides to pass a law against wearing green tennis shoes on a public right of way, I would expect it would have the authority to do so. I would not, however, extend to it the authority to ban the wearing of green tennis shoes within private dwellings in places not visible from the outside. Not because of any inherent "right to wear green tennis shoes", but rather because such a law would be inherently unenforceable without giving the state arbitrary powers to invade people's property to check on their footwear.
One principle which isn't in the U.S. Constitution, and probably isn't any state constitutions, but should be in all, is this: a person should not be punished for performing an act which a reasonable and knowledgeable person would have believed to be, de jure or de facto, legal. I'm not sure, but I would expect common law recognized the principle to some extent; certainly the jury system used to. Acknowledging this principle would help the USSC avoid and unwind some horrible precedents, by finding that the defendants in a criminal case violated a law that was constitutional but which they had reason to believe was not. Such a finding would block prosecution in all cases prior to its issuance, but would allow prosecution for acts committed afterward.
ping