What I don't believe is that it didn't take a lot of mental gymnastics to get there.
To get to the point of being able to have sex with another women, no question at all, I agree with you there. That's like a study on mental gymnastics, both figuring out the right lies to tell her, the right lies to tell your W, setting up the situation where sex can happen. I'm exhausted thinking about it!
That's why the line, "I didn't think of you at all," is so infuriating. It is so obviously a lie. I don't believe for one second that my H still loved me the entire time he was cheating. He did not care about or his children at that time. He only cared about himself.
The last part, yes, he certainly cared about himself more than you, his children, and other things in life, no question at all about that. As an aside, that's why I have so much trouble with the "broken wall flower" talk we often get around a cheating wife. WTF, really people? This person isn't "broken" they are selfish as f**k and breaking other people around them. No, I don't think my wife cheated because she was "broken", I think she cheated because she's selfish, shocking so during the A (and before it if we take the sexual denial and other crap she did to me into account). Funny thing, I'm the one who's always thought of myself that way (selfish), and she's the one who actually is. Hilarious, right?
The first part though, I really can believe that. I've used this analogy before, but imagine your H loves to eat your cooking. And that you're a very accomplished chef. If he goes out to dinner with his buddies to a nice restaurant and enjoys a meal there, is he thinking of you? Is his enjoyment of that meal an indictment of your skills in the kitchen? IMHO, no, it's not, in fact, in that situation, I doubt he's even thinking about your cooking, he's just enjoying the meal in front of him. I think it's that way for a lot of the APs I know. They just aren't thinking about their wives, their families, what they have to lose at all, because, if they did, they wouldn't cheat, the risks are too high and the payoff, too low, even for me, who might be (per comments in other threads) the most sexually motivated man who ever lived.
You can't think about the downside, you have to compartmentalize it away.
But I really do believe that first sentence, I think it's entirely possible he never thought of you (or your cooking) at all, it was just some fast food on the way home from the office. I know that's likely not all that comforting, but, at the same time, if this is a major pain point for you, perhaps it does help. Men typically have affairs to add (sex) where women more typically have affairs to replace (their husbands). If that pattern holds for your situation, then it's entirely reasonable, IMHO, to accept that he never stopped loving you. The problem is more "this is how you treat people you love?!" than it is "why didn't you love me".
The most common rationalization I hear for the first, and I'd be curious if you heard the same is "I didn't think you'd care". Which, expanding it, "You didn't really want to have sex with me anyway, so, what difference does it make if I get it somewhere else". That's a really common one that I've heard from cheating men, and, I must say, I felt exactly the same way before my W's A. Like sexual exclusivity to her really didn't matter, she didn't like sex, so what difference did it make if I got it somewhere else so long as I kept providing the things she did like (money, stability, friendship, etc). It's would have been a very compelling rationalization for me if I'd cheated, "she won't care"; while a complete lie, does, on the face, seem reasonable. I don't really like fixing the plumbing, if my wife hired someone to do "my job" at home, I wouldn't care very much. Now, I want to close and say this is COMPLETE BULLSHIT, of course she'd care, and it would be incredibly painful to her, but I'm trying to give the counterpoint, it would have been very easy for me to slip into the mindset that "She won't mind as long as it's just sex". And I think that a lot of men do just that, certainly a lot of the men I know do (and they are ALL wrong, every single one that's been "busted" has had a destroyed BS, as I'm sure all of us can easily predict).