It seems almost incomprehensible but it does seem like people have a capacity to put an affair like that in a separate box and pretend they have two separate lives. My wife did this for 18 months and said - all I can say is that the longer it went on, the harder it got to say anything.
Tim is right it is a big negative that she was caught rather than confessing herself. On the other hand she is at least saying the right things about what she now sees/wants etc. You have a really difficult time ahead of you, if you are like me. You may decide to try to rebuild (I am, and it is working) but even so you have years of memories that you have to completely reassess. Relive basically. So you relive some moment that you now realise was proof of the affair, and you get a powerful reaction as if it were happening right now... Except it isn't so you can't fight or defend yourself. It is incredibly stressful and it is no good lashing out at your wife when it happens. You have to come up with some strategies for it. Good luck, you are not alone.
Maybe it is okay, maybe it will be okay.
BS, d-day Feb 2017, 16 mth affair.