blueboy, it's only been two or three weeks since you started piecing, it will get easier. Feel those emotions, process them, take the time you need to do that. You may decide it's not what you want, that you can't do it, but don't make that decision from an emotional place, wait until you are happy with yourself and decide what you want your future to look like.
In the meantime, work on accepting what has occurred, ask the questions you need to (or don't if you don't need to), really process it and try and put it in the past. Don't let yesterday's pain ruin todays possibilities..
It is hard, but it does get easier.
Ok, so I wrote the above then I went back and re-read the start of your sitch to refresh my memory. Let me ask you something, you say that you had inappropriate contact with someone else early in your M. I'm assuming your W found out, that you two worked through it, and both you and your W became happy in the M again. Keep in mind that your W forgave you for your indiscretion, she moved past it and found happiness with you again, can you or will you do the same?
I'm not saying what you did in the past justifies what she did, I'm only pointing out that you two were able to work through it and be happy again, and hopefully you two can do the same again (if it's what you want).
M - 9 1/2 years 5/5/16 - Bomb drop - 3 week EA 10/31/16 - We sold house 01/10/18 - D Finalized