But just for reference purposes, adultery is only a basis for divorce in Texas; it isn't against the law there and hasn't been for a while.
After doing some state-by-state digging, I have learned a variety of startling things, among them the following:
Yes, in Utah adultery _is_ illegal; it's a class B misdemeanor.
For reference purposes, having sex with a first cousin in Utah (you can _legally marry_ your first cousin in several states, FYI) is a 3rd degree felony. Child bigamy (perp is married, and cohabs-in-the-sexual-sense or purports to be married or whatever with someone under 18) is a 2nd degree felony.
Not all laws are created equal, but some people are having a leetle bit of trouble keeping up. The whole first-cousin-marriage = felony incest thing keeps surprising me; I'd like to know if they are prosecuting married folk who move in.