I think I know because H told me when he first met OW. They met on a plane and she was coming to our area for a girls trip. He actually told me that she and her friends seemed like really fun women and it'd be cool if I could go out with them. I think he also mentioned at that point that one of them was going through a divorce. (I believe they swapped phone numbers at this point and H was also telling the group to give one of his friends a call who lived in the fun city the "girls" were visiting). At that point, he had no reason to lie.
Possibly. But she probably did.
Please don't be naive re: your husband's honesty with you. I've never seen someone caught up in an affair yet that DIDN'T lie. Ever.