As usual Bigger is spot on. Waiting for your wife to make a decision is not in your best interest. You need to tell her what her choices are. She can end the affair now, cut all ties, switch jobs, start IC (do NOT start MC).
You should seek out his wife and tell her. She has a right to know. I waited five months before doing so and I highly regret it. I was using that as leverage against my wife's AP in hopes that would keep him away from my wife (foolish in hindsight). Once I told her I felt better about myself. As predicted my wife was very upset, said I should have talked to her about it first, said I didn't consider the possibility of his wife coming into my wife's work and making a scene.
"What if she did and I lost my job? My coworkers would have found out!!" to which I replied "Where was this concern while you were having your affair?" That ended that BS.
Tell his wife. Get tested for std's. Tell your wife she either does what I wrote above or the relationship is over.
This is zero chance I would let my wife go on a business trip with this guy. There's no reason for her to not let it turn physical. He is just waiting for her resolve to soften, a few drinks after work at the hotel bar, her being upset that you found out and venting to him, you can assume the rest
Her going away will be hell for you because you are going to wonder what she is doing every minute. Even if she checks in and tells you what she did all day do you think you will believe she is telling you everything? You will forever wonder if anything happened for the rest of your relationship
In the early stages of discovering an affair your brain is in shock. Emotions run rampant and can change from minute to minute. It took me several months before I felt like my feet were firmly back on the ground and I could make clear rational decisions. Like many others in the beginning I was scared, I was doing the Pick Me dance, I was comparing myself to the other guy. I saw 27 years of relationship vanish in 30 seconds
Thankfully I found this place and got some amazing advice from people who have been on both sides of an affair so I was able to get better perspective and with that advice I was able to make demands that were in my best interest knowing that my wife could say no and that would be the end of the relationship
You have found the best place to get advice and support