Cheating has different consequences in different places, I searched around and gathered the interesting ones. Some really surprised me.
US Military: up to a year in confinement plus a dishonorable discharge, which entails the forfeiture of all retirement pay.
Michigan: life sentence!
Pennsylvania: 2 years imprisonment
Maryland: fine of $10!!
Taiwan: jail
Muslim-countries: in some countries up to death penalty!!
Pakistan: a crime under the Hudood Ordinance. The Ordinance sets a maximum penalty of death!
India: can be sentenced up to 5 years, for men only!
Sources:
http://www.helplinelaw.com/docs/criminallaw/adultry.php
http://usmilitary.about.com/od/justicelawlegislation/a/adultery.htm
http://news.bbc.co.uk/2/hi/asia-pacific/7786985.stm
http://www.dawn.com/2005/07/13/nat2.htm
http://www.slate.com/id/2091777/