<human>: Could you distill the essence of the text into 1-3 sentences?

I really have no idea where to start. We have been married for 7 years, together for 9. No children. She works with a married guy who she texts constantly, jokes around with constantly, they get lunch together sometimes, and he will sometimes come to our house to have a few beers after work. They have worked together for about 4 years and I have not suspected anything until recently.
I don't want to give too many details on how I know, in case one of them is a Redditor but I have proof he has been at the house when I have been away at work. I'm just playing it easy now as I get more information so I didn't come right out and ask her if he was there, but she didn't tell me he came over that particular evening even after some prodding from me. After that I did a little snooping and I found some nude photos on her phone that were not meant for, and that she never showed me. She also adamantly refuses to let me take any of her. So that brings us to the next issue. I matched up the timestamps of the photos and checked text message times. A few of the times match but just text messages until about three weeks ago when I found one MMS message to him from her that was at the same time a few of the nudes were taken. She's sent regular images to him, so I don't have any proof other than times coordinating. I'm really trying to not believe this could be happening.
I don't really have anything else to go on, nothing else seems out of place or weird. She still seems to love me, we still have a decent sex life, we still do things together, etc.
<bot>: Wife works with married guy who she pals around with, suspect they may be messing around. Found a nude photo whose timestamp matches a MMS message to him. Everything seems normal still. Don't know what to do.