Welcome to SI. Sorry you find yourself here with the rest of us, but you will find a lot of support, comfort & wisdom here.
I strongly suggest that you read
(Calling all BSs by Nomadlady in General---I just bumped it for you)
It puts your situation in a nutshell
It sounds like you are blaming yourself for your WW's A. It is not your fault. All marriages go thru ups & downs, times of distance, but you both took a vow to ride it out thru thick & thin.
You did not hold a gun to her head & force her to cheat. She allowed herself to do it because something is broken inside of her.
Would she be willing to join SI & read/post in the WW forum?
Your #1 priority right now is to take care of you. You might want to read some of the threads in Just Found Out, (Great Posts for Newbies, Tactical Primer, Boundaries & Consequences, & 20/20 Hindsight.)
All of us BSs know exactly how you feel, & we have your back. Sending you strength