I'll use a real life example. One of my best friends suspected his partner of cheating, she went out one night, told him where she was going and he didn't believe her. So he asked me to go with him to follow her, which we did. We went to the place she supposedly was going to and found her car wasn't there. Obviously he couldn't find her to he went home. He didn't mention it to her and then worked on finding out what is going on. She kept all her stuff password protected but he managed to get into her email account. All of her inbox was clean, as was her outbox but she forgot to delete the emails in drafts which of course had incriminating evidence (only 2 emails, but it was enough).

He came clean with her and told her how he found out, but instead of it being about the fact he found her cheating it was about him "going through her email" and she threw a fit blaming him for being a psycho following her. About 2 weeks later It actually got back to me on the grape vine that I was involved in 'stalking her' and not the fact that she got caught sleeping with another man.

I've noticed this shaming a lot, people seem to place equal blame "Well he went through her phone and caught her cheating, so he didn't trust her, what an ass". My advice is ignore this social haze. It is all full of agendas. If you have good reason to believe someone is cheating then do yourself a favour and find out.