Go with your gut feeling. If you think something is wrong, it probably is. "When in doubt check them out".

At the beginning of an affair the mate that is cheating is more attentive to his spouse.

After the affair has been going on for a while the person cheating seems to find fault with the person he/she may be living with to try to justify the affair in their mind.

Cheating spouses stop showing interest in what’s going on in the house. They stop doing any fix ups in and around the house.

Cheaters may have a more or less sex and unexplained sexual requests.

The cheater has a definite change in attitude towards the mate.

Another sign is MONEY. "If someone wants to play they have to pay". It’s not cheap to cheat. Look for unexplained spending habit.

Grooming habits will change. Cheaters will be more attentive to the way they dress, look, and do their hair.

Physical signs to look for to determine whether or not someone is having an affair are dinner receipts in their pockets, pieces of paper with phone numbers & address on them, and unexplained charges to credit cards.

Claims to be working late or going out with friends after work.

Pay attention to telephone calls when your mate has a tendency to whisper or gives a quick answer and immediately hangs up or if the mate is on the internet quickly closes the page when you walk into the room.