Bc39, I know that in my case (and what I've read in most cases), the spouse slips. After my initial confrontation about my wife EA, she and I reconciled - or so I thought. Slowly, over 9 months, my wife started pulling away again. I didn't really notice it happening at the time- until I got the ILYBINILWY talk from her. She insisted, no SWORE, that there was no contact with the OM. I believed her. I thought it was me (mostly because she told me it was me :)), and she told me she didn't know why, but she felt "broken" inside. She couldn't define what "broken" meant, but she used it often in the long months to come. Well, turns out she was talking to the other man- more and more, in fact - she had just gotten better at hiding it from me. I knew in my gut that something was amiss, and I was right. I finally did some snooping when she was out one day and boom- found the evidence of her EA restarting 8 months before.
Now I know that when she said "broken", she meant sad and torn about leaving her children to pursue another man. It was her way of describing the feeling of being trapped.
You didn't address my question- are you sure there is not contact with the OM? What are you doing to make sure that no contact is made while you rebuild? It seems awfully odd to me that she is pulling away like this- I'm sure your gut is telling you the same. Is the OM's wife aware of the EA and taking steps to keep her marriage intact? Don't let wishful thinking and trusting too early lead you into divorce court. Take the appropriate actions to protect your marriage while you can, don't say "coulda, shoulda, woulda" when it's too late.