[Sir Francis Dashwood]

Where is adultery illegal?

In a Divorce Court, it is a matter of the legally binding contract in marriage...

While you probably won't face crimminal penalties, civil penalties such as award judgements for alimony, spousal support, child custody, etc., are all punishments that can be imposed by the courts for breech of contract.

[11th Earl of Mar]

Where is adultery illegal?
In a Divorce Court, it is a matter of the legally binding contract in marriage...
While you probably won't face crimminal penalties, civil penalties

Which is why Santorum's remarks were off target.

The Texas case DOES involve CRIMINAL penalties.