Thanks for your replies and encouragement. This is an update where we are:
Where we started:
1) My wife told me everything, all the truth and probably the bits I did not want to know at the time. But I knew everything. She answered every question and it hurt - badly.
2) We then sat down and understand what and why this had happened, again a lot of talking and a lot of hurt. But at least I and my wife both understand and agree why.
3) I confided in 2 people (1 who had been through it before) and my mum. The reassurance I had from these people was great and at the same time they (especially my mum) was very constructive towards me (not that she expected this to happen but more there was a risk this would happen due to x,y and z).
Summary
1) Once you understand the facts, the one thing that is clear is that my wife wasn’t looking for a person but a different situation; it just takes anther person to build the situation.
2) Even though my wife did the ‘dirty deed’, it was a shared set of circumstances that led up to this.
3) It was clear that even though I wanted to ask the questions and say my piece, that my wife has to do the same thing, thereforeeee limit the anger and plenty of listening both sides (walks help massively not facing each other, side by side, fresh air. Also a long drive helps too).
Next:
The anger is hard, knowing the details make me re-live them and thereforeeee I have to deal with them. Able to communicate and ask questions helps with the reassurance and trust, it hurts just has much of my wife to answer then it does for me to ask and listen.
The one thing is definitely clear, the emotion that me and my wife feel to each other, we haven’t said things in a way to each other for a long time.
It is very sad that our marriage had to go through this, just because of principals, points of views and lack of communication.
Things are getting better and there are more positives than negatives now. So fingers crossed
We are talking about relate. So will post in a couple of weeks.