i agree with everything Another Stander has given you except the issue with your confronting your W about the EA... i think you were right to do it...
Sorry I did not explain what I was talking about very clearly, when I was telling him to "stop doing that" I didn't mean confronting her, I meant snooping. Sometimes some snooping is required to find out there is an A taking place, but once you know that then in my opinion it's kind of pointless to keep snooping. It's real easy to misunderstand the info you've snooped, and to draw the wrong conclusions. For example, early on before I found DB'ing my XW and I were going to MC and were given some forms to fill out and turn into the C beforehand. My W gave me her filled out forms to put with mine to give to the C. I snooped and looked at her forms and saw she had responded on some of the questions that she had been physically abused. I was shocked! I never touched her in a harmful way, immediately I tried to spin it into something, was she setting me up? Was she building a case against me to use in divorce to make me look abusive? Then when we were in MC the C read it and asked her about it and she explained how a BF from 30 years before had threatened her with a knife and said he was going to kill her. So the info had nothing to do with me at all. This is what I mean, when we snoop and see things we're prone to spin them into terrible things without really knowing what they mean at all.
As far as confronting about an A, yes I do agree with that. If you know an A is taking place, then by all means let them know that you know. Just expect them to deny, deny, deny. Don't believe the denials. When they demand proof just tell them there's no need, you both know what's going on. Don't tell them "I looked at your FB messages" or "I looked on your phone" or whatever, because what's the point? You're just giving them ammo to paint you as the bad guy because you are "invading their privacy." Don't give them the ammo, it's enough that you know, and you don't owe them an explanation.
Also once you know there's an A, is there any reason to keep snooping? I mean that's about as bad as it gets, there's no "good" A versus "bad" A, they're all bad!
I hope that makes more sense than what I typed before
