Thanks all for your thoughtful and thought provoking replies, I've learnt allot about my situation and myself and how I plan to proceed.
I'm getting my W to write a timeline of the EA and encourage her to leave nothing out, obviously dates will be sketchy given the timeline but the interactions won't be whatever they were (PA).
Then I'm going to hit her with a poly to prove that timeline isn't more lies and half truths anything but full, frank and total honesty will be terminal for our marriage.
Anyway thanks to you all I am now much more comfortable with whatever and however this turns out. I read the 180 and have implement my version of it, I call it the 135. I woke up this morning full of purpose because no matter what happens I am awesome and I'll be just fine with or without her.
The more she's talked about it the more I'm being swaying by fact my W's father died in her mid teens which totally rocked her world as he was her world, and she viewed OM as a sympathetic father figure (he is 12-15 years older) who listened intently and told her the nice things she wanted to hear, things a Dad might say. Please comment on this as my bull**** filter is clearly not functioning 100%. The email trail from both of my discoveries align with this.
She has been at painful lengths to say there has been and never ever was any PA. Too me there is a possibility there was before we were married. She is convincing, but pathological liers are aren't they!!
The bottom line is I gave my W a 2nd chance when many wouldn't have and she slammed that goodwill/trust (some say naivety) back into my face then lied to my face to cover up detail.
I, for one, think you're doing the right thing. Your reactions may have started out a little rocky, but that's hard to prevent.
None of us, including you, can say for sure whether she had a PA with this man, but I simply don't see the signs. I think, at worst, they may have been physical before she met you. From what you've read (which is obviously not all of their interactions over these years, granted) you haven't seen anything that points to romantic love on her part, let alone anything sexual.
I stand by what I said in my previous post on page 1 - that she is fully aware of HIS feelings towards her, however she does not feel the same about him. She MAY have tried to go that route with him prior to her relationship with you, but that's neither her nor there, IMO.
That said - she should not still be in contact with him, constant or otherwise. But not because he's any type of threat to your marriage. More because this is entirely disrespectful to you, your feelings, and the marriage as a whole.
There are people out there who can maintain friendships with exes, or are comfortable with their partners doing so. However, in the vast majority of those cases, neither ex views the person in a romantic way. This guy does.
That alone should be enough for your wife to have put a stop to this years ago.