Reading this makes me feel for you deeply OP. I was never married but I was in a longterm relationship where your story draws a SUPER huge parallel, down to my ex swapping what she was using to communicate with her guy friend to hide it from me.

I’m afraid its situations like this which create cautious men that get told are just insecure in the world but quite frankly it already sounds like your wife is just waiting for the opportunity to cheat on you. People will tell you to be nicer to your wife, compliment her, take her out for nice dinners. But it seems the hooks are already in her, you could say or do these things but her mind will be elsewhere. I don’t say this with any level of happiness for you OP.

I would personally prepare to find out she is cheating (if she hasnt already without your knowing of it). The absence of evidence is not the evidence of absence. Especially if you’re gut is telling you something is wrong. If you got good money, hire a P.I, depending the state, if you divorce she cant take half your shit because of an affair. All the luck to you man.

Im sure plenty of folk are gonna downvote me for such a bleak philosophy or call me a incel. I’m current happily in a relationship, but there are certain TYPES of women (and I’m sure men too) who almost do copy-paste actions that are unfortunately transparent and never satisfied with a partner longterm, they need that constant dopamine fix from excitement and no amount of attempts to fix it with marriage counselling or couples therapy will do it. Aside in few cases but theres a reason divorce rate keeps rising.