The first sign is if your spouse suddenly does not want any sexual contact or sex. This could mean that they are getting it from somewhere else.
Do not allow you access to their computer. If they do not allow you access to their computer or have passwords on their computer this may be signs of a cheating spouse. Most cheating starts online and progresses to face to face.
They suddenly have to work late. If they are the only ones that work late at the office then they may not be working at all. Also look out for trips to business meetings in different cities.
Their cell phone is on silent. Most people will place their cell phone on silent if they want to hide incoming calls or text messages. Also, if they carry their cell phone with them at all times and never let you see it then this could be a sign as well.
Drastically change their wardrobe. If they go out and buy new clothes and a new haircut suddenly this could definitely be a sign of a cheating spouse.
