I posted this yesterday, and many of you seemed to get really invested so here is the update!

My wife decided to be very upfront and open with the guy. They went on their daily run, but as soon as they were away from their hotel, she stopped and said she had things to say. It went something like "I talked to my husband last night, and I told him I had a big crush on you." He was pretty shocked, but then responded that he was feeling the same way. He was not going to say anything or make a move because she is married, but he has been separated from his wife for almost a year, with the divorce happening this coming winter (thats why he's on the trip by himself).

My wife told him I was completely okay with it, but that she wanted him to understand that whatever happens ends at the end of the trip, that she is really happy with me, and that she has no intention of changing anything. They both agreed that they needed to let all this simmer a bit, went for their run for real, and then joined the group for the day's scheduled activities.

That evening, after her mom retired to her room, my wife went to see him in his room. She went in and he gave her a big, long hug. She told him she couldn't stay long, so they sat on his bed, with their feet touching. He said he would have never imagined her doing this, she said she couldn't quite believe it was happening, and they laughed at how awkward it was because they've both never been with anyone else in 20 years. And then they started making out...

It went on for about 15 minutes and she was really getting into it, but told him she really needed to get ready for the next day and get enough sleep. She went back to her room and texted me "Something happened, can we talk?" (She's 12 time zones away from me). My heart skipped a beat when I saw her message and I called her right away.

She told me everything, she was so giddy and excited. We had a lovely conversation, I felt so connected to her, and to my relief, didn't feel jealous or insecure at all! I have been fantasizing about this for so long, reading stories and advice on this subreddit, but I kept wondering how I'd react if it actually happened. The reality is that I am genuinely happy for her (and turned on, not gonna lie!) She said she couldn't wait to come home to me full of that sexual energy, and she felt that this was a whole new level of trust and care in our relationship.

They both agree that they do not want anyone to know about it. It shouldn't be hard, there is usually nothing planned after dinner, and her mom is always in bed by 9pm.

Thanks for all the advice I got in my original post, many people also reached out on chat and were super helpful. I am so grateful for this subreddit, it was by far the most helpful resource I found as I realized I had this kink, needed advice on how to talk to my wife about it, and to know about the flurry of emotions that would come up. It's only the beginning of a whole new adventure, my wife is now interested in swinging together too :)

I won't post more updates, I think I shared what needed to be shared. Lots of people reached out on chat to hear graphic details, I'm not interested in providing masturbation material...