Ok I know it was unreasonable to read them, but I'm bothered by what I found. Background - he has a Facebook friend, female, they've not met in person, became friends after meeting on a group related to a hobby. Ok fine, I think. I've never been controlling about his social life, have always said I trust him 100%. They've been friends a while, Facebook settings somehow used to show me things he'd commented on, so I would sometimes get her posts in my feed, this doesn't seem to happen anymore but I've been aware of her a while, and used to joke to him that she was his secret admirer, he'd laugh it off. I've never had this reaction before to any other female friends but I can't actually remember what it was that made me think that way about her. She recently sent him a daft post, a silly meme, related to their hobby, in a PM, which he shared, I thought it was very funny and asked where he'd found it "oh somebody sent it me" when I asked him who he told me it was her but normally he'd have just said "Dave sent it me" or whatever. I could tell he was being a bit cagey. It bugged me and I ended up looking at her feed, and then at their PMs. She often posts about how hard her job is, dealing with unpleasant/awkward people. She sometimes mentions mental health - depression and anxiety. And talks about how stressed and overworked she is. He is full of blatant admiration for how she soldiers on (she does charity work as well), massive sympathy for her struggles in general. "give yourself a break you deserve it more than anyone". It's nice to see him being kind and encouraging but I really struggled with my mental health when the kids were young and he didn't deal with it at all, just pretended it wasn't happening. I've done the lions share of looking after home and kids, The teenage daughter years have been horrendously stressful, we've been through some real traumas, which he basically let me deal with myself while he carried on with his own work and social life as normal. This is my life, I just get on with it, but having not ever had much admiration, sympathy or recognition from him for what I've done it's bugging me to see him giving it to another woman. Her messages are also full of admiration for him, kissy emojis and "oh I do so hope we get to meet one day, you truly are amazing" as I said I have always trusted him, never crossed my mind he'd have an affair but I would actually be really worried if they were to ever meet.
I know I was wrong to read his private stuff but am I overreacting to what I've found? Sorry for the long post, I'm struggling with this a bit and feeling too ashamed of myself to talk it out with my friends.