It seems like there's a LOT going on in your relationship. Shattered trust on both sides and a lot of duplicity and anger.

Honestly, you need to take a long look at where you are in your marriage and if it's even possible to save at this point. If you think you (and your wife) can put your hurt & trust issues aside and move on without resentment, then I would recommend counseling. But if you don't think that's possible, then it's better to divorce than to spend the next few years growing more and more bitter/resentful/angry at each other, only to divorce anyway.

I think what she did was really awful -- you deserved to know that she was pregnant -- but I do think that you're severely downplaying your own transgressions. Saying it was a "brief" FWB that happened "years before" and caused a "fight" is acting like what you did wasn't an awful, painful betrayal of your own. She should not have reacted the way you did, but you also need to acknowledge that you disrespected your marriage as well. Honestly I don't think this relationship is salvageable. Both of you have done toxic things to each other and I don't think there's any moving past that.