I (39M) found pictures of a guy hugging all over and kissing my wife (37F) of 11 years at a music festival last year

not really sure how to get started with this one but..
she left her Mac open one day and we have had a bit of a bad spell here lately, happens from time to time since we both work stressful jobs and have a special needs child. when things are good, things are great and we have only been having issues the past 12 months or so, really nothing before then but minor arguments and small fights about nothing. over the past few days I have brought to her attention that I am not really sure how I feel about this and I'm not sure how comfortable I am moving forward until I feel better about this
I've had a feeling that she was messing around, or trying to, with someone... ugh.. so I looked in the Photos app and saw nothing out of place... then Hidden and saw that she had pictures (8) of a guy that she knows from work, hugging all over her extremely close and tightly, and kissing her on the cheek in each picture. one was a movie as well where she continues to hold on to him and then realize she's taking a video. huge smile on her face and you can tell she's intoxicated heavily.
I asked her about this over text since she was at work and then immediately the pics were deleted from Photos. I did airdrop them to myself though before so I have them in case any legal issues come up and I need to have proof of an affair. after they were deleted - she said what? what guy? I was with (my friend from here) etc etc and tried to play it off and then blame me for looking at her stuff. I know that is wrong, but I mean look what I found?
we talked the rest of the time while she was at work and I did get really upset, said some things that I probably shouldn't have but it is just really concerning that she had them hidden like that, and saved from last year.
these music shows were not only last year in August and September, but 2 hours away from where we live and a month apart from each other. she went with a different friend (her friend is a female) from here each time. the first time she said it was coincidence that they ran into each other but she did admit to telling him she was going to that other one and they should meet up again. I was not invited to go to any of these shows, either btw
her and this guy are friends from work and I guess have had a rapport from that but I've never met him, don't know how old he is or anything like that. she said that he does know that she is married
I just wanted to know why she would allow that or if she tried to stop him and her response was "I am sorry, I just wasn't thinking"
she admitted to drinking a lot, he was drunk as well - something that she never does here or with me, ever. I dont really find that excuse valid.. she has really bad panic attacks when she drinks a lot and before when she's done that, she's had to call me at night and I have to talk her down some. we both kind of agreed it might be best for her not to drink a ton so then that doesn't happen and that did seem to help the last time she was away for a work trip and several other times when she's been away.
this guy also was staying at the same hotel as her the first concert. I never got a call from her that night, so maybe she didn't have a panic attack.
she swears up and down nothing else happened, but I'm just not sure how I can believe her at this point, or trust her going forward. nothing like this has ever happened (that I know of)
so back to this "I just wasn't thinking" excuse. sh..e wasn't thinking of husband of 11 years? her child? just not thinking of anything? this has spiraled into a huge argument now going on a few days and I really just do not know what to do
how can I trust her going forward? if she has done this and never thought anything of it, what else has she done in the past and just doesn't have photo evidence of it?
on the other hand, it was a kiss on the cheek but why take so many pictures of this when you're married? they took some in the car on the way there, several at the venue and the time stamps were all over, from like 7pm-11pm
am I really overthinking / overlooking this or do I have a valid reason to be super upset?
and again --- I'm upset because of the "I just wasn't thinking" excuse because it worries me that she thinks that is a good reason for this. what else has she done when she's not been thinking?
another fun fact is that there were a TON of videos of her / pics of her that she had taken "for me" just never sent me, going back over a year, in that same Hidden folder. she swears that she hasn't sent them to anyone or shown anyone. she just took them and then never sent them to me either, which is pretty strange all in itself.
oh another fun fact, she's flying across the US in 2 weeks to go to a show with her friend. great timing, right?
I appreciate any advice here, guys. again, I might be over thinking and that is fine too, this hopefully will feel better to get some assurance either way
TL;DR - found pics of a guy hugging and kissing my wife on the cheek at a music festival and it seems like she's lying about other things
EDIT: the friend that she went to the festivals with is a female each time, this guy was just "there" at both of them but is also from our town and where she works. I should have been more clear
hope your Saturday is going better than mine!


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