There are a number of precautions you can take to ensure that your spouse is not fooling around.

  1.  Make sure you know all the email accounts that he (she) owns
  2. Get the login name and password for each email account
  3. Check every email account three times a day. Also check all messages that have been sent, received and deleted
  4. Check his (her) Facebook page every day
  5. Check all the tweets he (she) sends and receives every day
  6. Check all postal mail he (she) gets every day
  7. Check his clothes in the laundry basket. Check if there are any unusual perfume smells
  8. Go with him (her) whenever he (she) wishes to go out for lunch, coffee, dinner, movie or theatre
  9. Check that the mileage in his (her) car is consistent with his (her) travel to work and back
  10. When he (she) is going on business travel, either accompany him (her) or ensure he (she) is traveling alone
  11. Check his (her) cell, check all phone numbers, calls made and received, sms sent and received