Gone are the days where he will have the perfume smell or lipstick of his girl, they have become smart enough to be very careful in this. The only way to know is through his cell phone. If he tries to hide his phone from you then there is something happening. Observe him when he is with his cell phone, take a note whether he takes his cell phone inside the bathroom or sleeps with his phone with him. If he is not separating his phone from him then make sure that there is something going on that he does not want you to know.

Apart from this the best way to know is through his personal behavior. He will get anxious often; when he tries hiding things from you he will tend to show it by accusing, acting in a insecure way and getting anxious.

The most important thing is that if he maintains emotional and physical distance from you. If you try to get near him too he may give some excuses.

Also if he suddenly starts coming late and tells you that he has gone out with his friends and if he is concentrating more on computer and his mobile phone.

If he avoids answering the phone when you are near him then there are chances of cheating you.

He may go for hairstylist and may start concentrating more on his physical appearance.

These are the signs which will indicate that your boyfriend/husband is cheating you. Do not panic observe him carefully and then react. Discuss it with your friend or family and then decide.