I feel calm and ok with everything. I'm not sure why. She put his feelings over mine and our kids many times. It's not hard to walk away in the face of that. If things work out down the road, then that would be cool, but I understand how i can be happy and healthy without this baggage and memories in my life. I love my wife, but right now, need time to be me and be a dad to my kids i haven't been the last 2.5 months going through all this.
You're feeling calm because you've integrated certain opposing realities that were impossible to hold in the consciousness at the same time. Like that your dear lovely wife, and mother of your children, to whom you've devoted your entire being, could be a cold, calculating cheater and liar, apparently without conscience or remorse. And that the only reason it still isn't going on is that you caught her multiple times. Those are hard realities to deal with, but once you accept that it is what it is at least your anxiety wanes and you can get back to functioning.
Making the decision to file for divorce is huge. It's equivalent to taking back the self that got trashed when she cut you off and started banging the other guy. You're still trying to hold onto a tiny piece of the past by saying that you might consider reconciling at some point in the future, but I think you know that once the break is made and you start living fully again, you'll no longer be interested in round #2 with her. How could you ever trust or respect her again? It would never be the same.
Divorce is hard while you're going through it, but once you're done there is clear sailing on the other side... a chance to build a new life that's really worth having instead of the big compromise. You're going to wake up one morning with the realization that your life is valuable, and you're absolutely worthy of real love and companionship... no more looking back over your shoulder, trying to turn disgust into a marriage worth having.
I think you should be moving forward with the D and begin giving up the little fantasies about who you thought she was or wanted her to be.