OP, your post resonated hard with me, as I too found out about my wife's 9 year long EA via a slow drip of Whats App messages and emails. In my case, she started with inappropriate flirty messages before we were married, but then escalated into sending nudes, dicks pics etc once we were married and continuing through to the birth of my first child.
I'm 9 months out, and I've mostly come to terms with "what" it was and "why" she did it. My day-to-day is no longer consumed by a swirling toilet of emotions. Properly processing my emotions has been a huge help. There are other threads on here that discuss this, but for me, it has meant sitting with the feeling and examining the physical manifestations and examining what triggered it. Often done through journaling.
All that said, its hard to escape the feeling that we have just reached an 'uneasy truce" where we are mostly just exhausted about talking about it. I say this only to give you a sense of what to expect. While it could be said we are trying to "reconcile" I don't truly know if that's what I want. It feels right playing outside with my kids knowing our family unit is intact, but it also feels fucking horrible knowing that for almost my entire relationship I was one of two guys she had feelings for.
It took me several months to find a friend to talk to this about, but when I did I broke down in tears from the sheer relief of it all. This community is great, but being seen by someone who loves you and knows you is invaluable. Take your time with it, but if you can find that person, know that it will only help.
I definitely don't have all the answers, but I suppose reading about a fellow traveler prompted me to express my support. Stay strong brother.