Is there anything more specific that makes you think there is an OM? Snooping is generally frowned upon here. Most will advise you not to. For me, I had to know one way or the other. I found incredibly painful things that haunt me to this day even though we are piecing. I hid a voice activated audio recorder in my W's car because I knew she was going places and likely staying in her car when she got there. What I heard was horrifying. But I feel I had to know. Only you can decide if its worth it for you to snoop. If she's not having an A and she finds out you have been snooping, it will damage the R. But if she is having A, I think you need to know that. Weigh this decision carefully.
Me: 48 y/o W: 47 y/o Together: > 20 yrs BD: Dec '15, then S 2nd BD: Mar '16, then I filed for D April '16: started piecing