It should always be a crime to have an affair, while married to another.
You have a legal contract with your spouse, and the spouse can sue:
http://myfamilylaw.com/library/alienation-of-affection/
That is a civil matter not a criminal one. It is a sin, not a crime. Whether that makes it better or worse is a question for theologists and philosophers. And what happened to ‘judge not lest ye be judged’?
Alienation of affections and other divorce related actions are civil matters-they are not crimes-contracts are civil matters, and the rules pertaining to them vary from state to state, as they should.
If affairs were a crime, then nearly every US president all the way back to Washington is guilty-and some like JFK, LBJ, Bill Clinton were a source of gossip and speculation that would make pres Trump look like a boy scout by comparison especially JFK. Most people vote for a president-not a priest or other clergy-to run the country-whatever they do that is legal behind closed doors is just to gossip and speculate about-people went overboard getting their thongs in a twist about Clinton’s womanizing, and look what happened-re-elected and still a popular ex pres, even if he is a total SOB personally...
Yeah tell all the men stuck in dry marriages they can sue their wife for alienation of affection. Its actually marriage fraud. Wheres the money going to come from?