Is suspecting an affair enough?

[nosmokinggun]

What would it take for you to tell someone close to you that you suspect that their husband/wife was having an affair?
Would you keep quiet unless you had concrete evidence, or would circumstantial be enough for you to tell them your concerns?

I'd never tell anyone I suspected an affair unless I was sure to be honest, I guess that would depend on how "circumstantial " the evidence was though.

I’d keep quiet without evidence. If you have evidence, say something.