SG,
Here are a couple of thoughts for you, as you continue to sort all of this out.
You've come to the determination that your wife did, in fact, love you while her A was going on and still loves you now? You are correct. Yes. She did and does. It's counter intuitive, but she did and does. Her feelings for you didn't have anything to do with this, it is important to keep that in mind.
Why did she do it, then? I don't know that anyone can get to a "why", but here's my shot at "how" many affairs (including your wife's A) happen(ed). I'll call it the dysfunctional bubble.
Dysfunctional bubble consist of the following:
Temptation: due to attraction to the other person.
Opportunity: due to working with him daily.
Denial: thoughts along the lines of the A being short term, victimless, no one will ever find out, no harm no foul.
Impulsiveness: what the hell, let's go for it
Rationalization x 10: I've never done anything like this before and never will again. A million other possibilities for rationalizing, including "I deserve and want some "fun" in my life.
Compartmentalization: Nothing else exits while I'm involved in this "victimless" act(s)
Suspended morality: See all of the above
Selfishness: Let me think only about me during all of this. She didn't think about you, SG. She didn't think about your kids. She walked into a fantasy bubble and thought only about herself; otherwise, she could never have done it.
Immaturity: Let me think about my short term desires and immediate gratification and dispense with adult thinking about all of the things I know are important in life and which I have worked hard to teach my children.
All of the above and more, I'm sure, combine to lead some people down this horrible path which has impacted everyone on this board.
So, the A happens. then, inevitably, B....O....O....M. The dysfunctional bubble is burst. The BS finds out. So, the WS reacts in different ways. Some choose to hang onto some of the ingredients that got them into the affair in the first place (see above). Some simply stay in their dysfunctional bubble and feel little regret and no remorse. BUT, when they feel HUGE consequences, (which is what is often recommended on this site and is exactly what you did, SG) sometimes their dysfunctional bubble bursts completely and they turn into mush. They realize what a huge, huge mistake they have made. This sounds like what has happened to SG's WS.
SG, your wife never stopped loving you. She just created a dysfunctional bubble for herself and screwed up your world, your kids' world and her world, and in your case, it does not appear recoverable. She THINKS it might be recoverable ("I'll follow you if you move, to prove I want only you, blah, blah, blah..."), but the damage is done. The consequences have arrived. And, just like a jail sentence imposed by a judge in a courtroom, a defendant promising that they are really a good person who made a big mistake and that they will never do it again, is generally not enough to prevent their jail sentence from being imposed.
I have no grand conclusion to this, but I can tell you this, I feel your pain, and I'm sorry this happened to you.