(((Bdell))) I'm so sorry you're here, but glad you found us.
I, too, found out about an old infidelity years later.
This presents certain difficulties. First, the WS has had the benefit of making things "okay" in his/her mind. S/he knows what happened, has compartmentalized it, and wrapped it in a myth ("I was lonely," "You weren't there," "You always rejected me," "Our marriage was bad then," whatever...) to justify it.
The WS has spent YEARS telling him/herself this story whenever the box into which s/he'd stuffed the lies threatened to pop open in his/her mind.
When the truth comes out, they are gobsmacked. How did THAT happen?! It was a secret, and you finding out wasn't part of the story they made up!
Don't be surprised if anger surfaces, in your wife, rather quickly. There will be an expectation that you "just get over" it. It "was so long ago," "and has been over for so long!" "It was only a few times" etc., etc., etc.
If you don't box it up and shove it into your attic fast, she will get angry.
I'm warning you: the impulse will be to maintain the status quo. To tell yourself, "at least it's over and done with. She's been a good wife since then." To rugsweep.
Please---don't do this. The secrets and lies MUST be dealt with because, as long as they exist between you, there is a barrier to intimacy.
Really, the affair is horrible. But worse is that, every minute that she's been with you since has been a lie.
THAT has to be confronted.
You can get through this--truly. If your wife is genuinely remorseful, you can sift through the damage together and reconcile.
The other dude has to go. That he was able to so easily and immediately get in touch with your wife is profoundly worrisome. There needs to be NO avenue by which he can contact her.
And that's just for starters. I'd get her started on a timeline--and go 180 until she stopped sniveling and got busy cleaning up her mess. (For example, the inn owner knowing you're not Mr. Cheater? That wouldn't happen if it had only been a visit or two several years ago. That lie is one she needs to address---and the timeline can help her do that.)
As awful as you feel right now, I PROMISE it gets better. No matter what the outcome, YOU WILL GET THROUGH THIS.
Be sure to stay hydrated. (I'd avoid alcohol.) Eat small, frequent meals or get protein supplements if eating is difficult. Take a good quality multivitamin. Rest when you can; if sleep is a problem, try dyphenhydramine (generic Benedryl) or melatonin or, if they don't work, talk with your doctor. Grief is normal; if it segues into depression, talk with your doctor, too. Exercise daily. Good self-care can help keep you intact during this most horrendous ordeal.
And come here, often. This is the best group of people on the planet, and the different viewpoints you will see will help inform your decisions.
ETA: I know this is obnoxiously long, and I apologize. But I wanted to add something in response to one of your later posts, when you touched on karma and questioned what you'd done to deserve this.
Bdell, this has NOTHING to do with you. I know it's impossible for you to really believe that now--but tuck it inside your mind, and let it stay there. As time goes on, and you observe your wife, learn more about her actions, and see how she's comported herself for the past several years---as things come to light---it will become clearer and clearer to you that NO, this is NOT about your deficiencies, but rather about her seeking to fill her own cracks and holes. There is something missing in HER that causes her to seek a sordid hotel relationship with another man. (And really, it doesn't matter HOW nice the B&B is, or how fabulous the dude looks on paper. Anything requiring the level of deception and duplicity of your wife's long-term affair is as seedy and sordid as if she were banging a meth-head in a burned out car. Seriously.)
As she tells you the deficiencies in you and your marriage (which she will, if given the opportunity), PLEASE stifle the impulse to internalize her negativity. Even if you don't believe it, tell yourself, "This is not about me. It's about her."
One day, you will know it's the truth.
You didn't do ANYTHING that makes your wife's actions acceptable.
Remember that.
ETA again: please consider telling the OM's wife, yourself, when you have more information to share. She, too, has been betrayed, and it might not be the kindest thing to require that SHE learn of the infidelity from the woman who helped destroy her life. Once you've checked more of the records, and have a more fleshed-out timeline, you can let the wife know, at least, when the affair started, where they met, and how long it lasted. (Sadly, I think you will discover it lasted longer than you have been told. I don't buy the "They were so memorable to the innkeeper because his skin was browner than his" story; it's not plausible in 2013.)
[This message edited by solus sto at 10:16 AM, December 16th (Monday)]