Oh boy, never ask a question or snoop on a phone when you don't really want to know the answer lol!
I think you should explain to W the next time she says you aren't trying that you would like to go see an MC to figure out how you can continue your marriage. Then in a more neutral space with MC a couple of sessions in you could give your requirement for transparency or how the thought of a POM makes you feel and what you need.
My thoughts are that it won't go so well if you do it on your own. I think there will be a lot of denial, recrimination and you don't trust me etc. at least with someone to mediate it can stay away from accusatory, as many of these convos turn out
