To me, just like the 1stwife's comment (and experience), it's pretty simple:
He told the OW he loved her for months. I believe he did. He certainly didn’t love me based on the things he said and the way he treated me.
It may not have been sustainable but the feelings were certainly real.
When I say the A isn't "real" I mean it from a more logical perspective - that the relationship - the FEELINGS - an AP-WS are really having isn't based in reality. Kind of like this:
Many years ago when I was single I met this "fantastic" guy while I was on vacation for 2 weeks on a remote island in Fiji. Super remote - only like 30 people there, very laid back, a lot of scuba, beach lounging, no electricity, no cell phone service, no hard line phones, and no internet - just generator and solar power at certain times of day, and many days spent playing cards and laughing and drinking under a palm-frond thatched roof open hut while a multi-day tropical storm poured rain - that warm balmy rain with a light breeze - just having a freaking great time in a setting that in this day and age is about as close to detached from reality as it gets - and romantic as heck too. It was immediate attraction, but I lived in Australia and he lived somewhere in England, so we spent the two weeks like they were our last. He was the ultimate "dream" guy - handsome, smart, blah blah blah - I thought he was perfect and imagined making it something permanent, and we even talked about that a bit without having any sound plan to do anything to make it so. At the end of the 2 weeks we parted ways and I actually cried at our parting and thought of him often for a while and then went back to my normal - graduate school, tiny (but awesome) flat, bills...life. We would exchange emails from time to time about nothing but "missing yous" and other unimportant mostly non-boring-real-life things - at first quite a few, but as time passed less and less.
Fast forward a year, dream guy sends me an email - I'm still single and he's coming to Australia and will be in my town for at least a month, maybe two, for work. I prepare, plan, look forward to it and he arrives. It's just like before, for the first week, but then we spend more post-work/school hours together as he ends up being there for about 10 weeks. He comes to my place, and it's clear he is less than impressed with my studies (at the time I was not studying law but literature, and an obscure genre at that which he thought was fanciful but not realistic as "how are you going to make decent money with that degree?"), and he doesn't like cats or pets in general, which my roommate had and I love, and a whole host of other things. He dresses a bit to ostentatiously for me (unlike the flip-flop and shorts clad guy I "knew" from the trip), and seems to be super impressed by things like status and fancy cars - things that even though I make a good living I would never buy as I find all that trying to impress others as tedious and unimportant. He is a bit of a neat-freak, and I, while fairly tidy, am not him. He is constantly interrupting our conversations to check in on work, which while I know is sometimes necessary, it seems too frequent to the point I'm wondering if he is trying to impress me with how important he is or trying to make himself seem more important for his own self-interest, and ultimately it just seems disruptive and a bit rude. He calls me "sweetie" in front of his workmates in an endearing not demeaning way, but I HATE this word like, barf-hate, so I bristle every time he says it... In other words, it became clear pretty quickly that we were not long-term compatible in any meaningful sense. I'm sure there were things about me that he wasn't a huge fan of but because he was leaving we never needed to discuss. He left, and we discussed my coming to England but I never really pursued it and he never really pushed, and we still exchanged emails for time, less passionately and less frequently, and then he just faded away. I have no idea where he is now.
Our time in Fiji was like an affair - nothing real getting the way - pursuit of pure enjoyment. And he seemed PERFECT. While I'm sure he mentioned some of the things I found to not be my thing while there, they were glazed over quickly. Only in the harsh light of even semi-reality was it clear that perfect for me he was not. But that reality did not make my feelings for him when we met - those two weeks and the year after - any less real. They were. I was really really really into him - the Fiji-fantasy version of him.
To me, my Fiji-affair was similar to an infidelity affair, minus the "excitement" of the forbidden, and his time with me at my home was much more real, allowing me to see him outside of the lens of fun and adventure. So, were my feelings back in Fiji real? Yep, they were. They just were based on an unreal version of him, and therefore were not reality-based. If that makes any sense?
So this is another long winded answer of mine - to the extent you were wondering if your WS's feelings in her A weren't real to her during the A, even if her A wasn't "reality" - I would say they were. While that hurts, I know, as I too came to the same realization about my WH now (something he freely admits today), she also was a willing participant in her own mental deception.
[This message edited by ThisIsSoLonely at 7:59 PM, Tuesday, September 12th]