I'm so sorry you're dealing with all these emotions right now.
I'm curious as to why she came to town on business, and planned to visit your FIL? Is she an old family friend?
Is it possible that his timeline felt very foggy after the affair was disclosed? Could he have thought he was telling you 2011 when he meant 2010? I'm not making excuses for him...it's just that I've asked repeatedly for a timeline from my WH, and he just can't seem to put one together at this point. All he can tell me is that one of his ONS affairs happened "last Fall". Well...it's Fall again, so a year has passed, and things still appear to be very foggy. I honestly believe my WH has a significant chunk of time that is very murky, because he was too consumed with balancing infidelity with his real life.
Can you go back to Oct 2011, and see if there was anything significant there? Could there have been a second visit? Could his dad have confronted him a year after that kiss? Again, not offering excuses. I just know, based on my experience, that getting dates/events mixed up has been a challenge we're dealing with in our marriage.
The words of praise...yeah...that was uncalled for. Again, who knows why he threw her name out there -- maybe he was worried that it would look obvious if he mentioned others, but not her...as if he was covering up something by not mentioning her name. Who the hell knows.
You have every right to be upset. But you also have a different husband today than you did a few months ago. He's in a different mental state, and he's more removed from the A. I do think you should discuss it before you go home as 1) It will eat you alive and 2) The kids aren't there.
Much love and many prayers for strength, wisdom, and transparency.