“He who is without sin ,cast the first stone”. I assume that you consider yourself as a perfect human being without any faults!
If a person wishes to commit adultery, that issue needs to be resolved between that person and his/her mate. No church or goverment has a right to judge them. If you were a Christian, you would realize that only God has the right to judge others on moral grounds.
I don't know what planet you're posting from but enfocing a society's morals is what government is for. And we still have laws against adultery in the US, but they are woefully underenforced.