Well if the government is going to go crawling into bedrooms, don’t be surprised if you find them in yours.
You are aware that immunity from government sanction is one of the Privileges and Immunities associated with actual marriage under outer rightful common law and therefor among the P&I covered by A4:S2:C1 or the other rights retained under the 9th Amendment?
So where (essentially local or state) government might lawfully have something to say about adultery what goes on in the marriage bed would be protected.
The sexual revolution whereby people reduced the pursuit of happiness to little more than who does what with their genitals was not either a new or a good idea anyway.