Answer:
If your really sure that your husband is cheating, one easy way to find out is hire a detective which will cost you money. Second is just go to him and ask him face to face so that way he will know that you know. But if the two of you is not on speaking term all you have to do is pay attention to everything his doing.
Most of the times us wives really can't tell if our husband is having an affair. But if we do want to know all the answer is right in front of us.
1- he will be taking a shower every single day
2- when he comes home and he look fresh like just got out of the shower
3- see if your husband cell phone is always in his pocket and on vibrate or silence
4- check his computer if he always change the password or always off when you are
coming to talk to him
5- how often does he comes home late
6- any change in intimacy
Over all you are the only one that can tell if he is acting different when his with you.