IMO, illusions screw up lives. The phone shatters a set of illusions, and that's immensely painful, but I think you'll eventually feel better off for knowing the truth sooner rather than later.
Right now you're probably in shock. You don't know what to do. You're probably angry, sad, scared, and ashamed. Your head is probably telling to go this way one second and another way less than a second later. You probably have trouble eating, sleeping, moving, drinking water....
All of that is normal. Being betrayed is traumatic and extremely painful. All the bad news, though, is countered by this: you can recover. You can feel the pain and let it go. Your feelings are all right on, even shame, though you have nothing to be ashamed of. You can process the feelings out of your body. It will take longer than you want it to, but you can do it.
My reco is to stay away from the stay or go question for now. Ride the waves of emotion until you get your footing again - that will probably take 4-8 weeks.
Unless you know you will choose D, I suggest reading the bull's-eyed posts at the top of the JFO forum and the following 2 threads:
https://survivinginfidelity.com/topics/324250/things-that-every-ws-needs-to-know/ - provides guidance in identifying a good candidate for R
https://survivinginfidelity.com/topics/497843/fear-vs-reality/ - should be self-explanatory.
A few of things to keep telling yourself until you believe theme
1) You didn't cause this. Your WS went of the rails by his own choice, because of his own issues.
2) You can recover, whether you D or R or wait to get more info. Take the time you need to make your decision. You'll affect decades of your life. That's worth taking some time to figure out what's best for you.
3) Again, if you're not immediately going to D, make sure you know what you want first. Knowing what you want is important even if you don't think it's accessible. Then act to get as close to what you want as possible.