Here are some warning signs to look for if you suspect that your wife is cheating on you.

No Longer Needy or Need Attentions From You
If she used to be needy and needed love, affection, and attention from you and then it suddenly stops she may be having her needs met by another man. If she no longer needs your affection or attention then pay close watch to her actions as she may be cheating.

Is She Spending More Time With Friends that are unfamiliar to you
Does she have new friends that you have not met and spends a lot of time with them? If so this may be a perfect avenue for her to cheat without getting caught. Her new friends are not friends of yours and have no reason to tell you the truth. These friends will happily cover for her when she is out and about with another man.

Anger Issues
Doe she no longer get mad at you for stuff that use to always irritate you? Does she come home and no longer yell that you have your shoes and feet on the couch? If so this is a possible sign of potential cheating.

Turn a Question Around on You
She goes out and does not tell you where she is. You later as her and she turns the questions around on you by asking "Where were YOU at?".

Gifts and Surprises
If she is suddenly buying you little gifts and doing favors for you like making nachos and acting like sh did 10 years ago when you first started dating, then she may be cheating. This is an often overlooked sign of cheating. She is showering you with gifts and favors because she feels guilty for her cheating.

Although these are common signs of cheating, none of these signs are definite indicators of cheating. If you suspect cheating then simply watch and observe and say nothing to her about your suspicions. If she suspects that you know she might be cheating then she will be even more careful. You want her to relax and think that you have no idea it is going on. This will cause her to eventually slip and you can be assured of having overwhelming evidence of her cheating.