Went through husbands phone

I went through my husbands Apple Watch when he wasn’t home and found weird msg’s between him and a new coworker who is much younger (he is 42, she’s 23) Nothing was blatantly inappropriate, some msgs about work and coworkers. Some about podcasts and tv shows to watch. They talked about how she was going to the bar for Halloween and he made a comment about missing those days (weird cuz he’s never been a big drinker) He sent a pic of our 3 month old and 3 year old in their Halloween costume and she commented they were cute. There was a pic of something she left in his truck at some point in the last week. He never mentioned that she was in his truck or that they went to lunch (I’m assuming that’s why she was in his car) he encouraged her to see if she could come on an upcoming work trip early next year that normally her position wouldn’t travel for. He also texted another coworker that he “shouldn’t take marriage advice from you because I bought a bought and didn’t tell Sarah” (me) - so apparently he also bought a boat and didn’t tell me??? I can’t tell if I’m overreacting or am I justified for being upset? I shouldn’t have gone into his watch but I don’t trust him to begin with. He’s never cheated but I dunno. He’s very closed off and doesn’t communicate with me in general about his day to day so I don’t ever know what’s going on w him or work. I’ve been acting weird and he knows something’s wrong but I just keep saying I don’t feel well. Do I let him know I saw everything or do I give it more time to keep checking his watch to see if something happens I tried asking about the coworker and he said she has a bf