Hello BiD:
I still feel like some things in your timeline aren't adding up. This forum (JFO) is to offer support to betrayed spouses in the throes of discovery, so I won't impeach you with your statements. I will simply say that this is a forum of anonymous strangers who have all been impacted in some way by infidelity. Together we have a pretty strong crowdsourced reservoir of wisdom and hard-won experience. But by the nature of these forums we can only offer advice based on what you tell us. That works best if you are transparent with us. Since we are strangers, you have no real downside to doing that. I sense you are withholding stuff, or shading in some kind of way. Just a feeling in my gut.
The confrontation with your WW at the hotel is, quite honestly, the most disturbing, hateful, disrespectful moment I think I have read about here on SI. I have read about many instances of a BH confronting his WW about having sex with another man. In many cases, she takes it further underground and sneaks around to continue seeing him, or lies to her BH about seeing him, etc. But I don't believe I've come across another thread where a wife, caught in a hotel with another man, looks her husband in the face and tells him to go away so she can continue fucking the other man.
I frame it that way for a reason. There are a few elements that most agree need to exist if R is going to work.
The first is coming to grips with the reality of who she is at present. At present, your wife is the kind of woman who will look you in the face and tell you to go away so she can fuck another man. You know this about her because she has told you this with her actions. Usually, when a person tells you who she is with her actions, you should believe her.
For R to work, she has to figure out what is broken in her soul that would lead her to commit such an act of express violence against her husband, and fix it. Until she does, she is not a safe spouse.
The second part is that "ephemeral matter of the heart". You have to be able to believe, in your heart, that you are her Plan A. I don't have any way of telling you how that works. It's different for every person. But in general, the experience here is that it can take years for you to reach a place where you believe this. It's a huge investment of time, energy, and pain by you. If you are considering making that investment, you want to be pretty sure it has at least a reasonable chance of success, because she is doing the work of fixing herself.
Finally, there is the question of the "line in the sand" issue. Every BH has one. It's personal and subjective and only you will know. Zirconia (above) talks about realizing that his WW left him alone to walk many miles home in the cold sleet, with bronchitis, so that she could have sex with another man. That is his line in the sand. There was a thread here where the BH's WW had unprotected sex with another man in the afternoon, then let her BH perform oral on her that same evening. His line in the sand.
Which brings me back to the confrontation at the hotel. As another poster has mentioned, this moment will be your companion, for the rest of your life. If you stay married to her, you will look at her face and periodically see her telling you to go away so she can continue fucking another man in a hotel instead of joining you and your kids on vacation. Can you see yourself reconciling from that?
On other point, as other posters have said, you absolutely should tell the OBW, right away. It's the decent thing to do.
What I am here to tell you, is that you owe the other betrayed spouse the truth about her marriage. She deserves to know the truth as much as you did. I'm going to guess this isn't his first rodeo, and he is putting her health at risk, and she continues to live in a lie. She may already suspect and just needs proof. She may not want to know. She may choose to not believe you. But she deserves to know.