Wall of text. Friday + beer. Sorry.
Man, I've been in the post A world for too long. Wet hair, lather, rinse, repeat... It breaks my heart to see people go through the same shit over and over again.
First, let me say I feel for you. Cheaters are just shitty people. Sometimes they are good people who do shitty things. Maybe one day I'll be able to distinguish between the two.
Your WW is caught in the fog. She is monkey branching to what she sees as a better deal. It may be that you are a higher quality guy, but in her eyes, the AP checks all the alpha Male boxes. Yeah, I know she's delusional but reality isn't a factor here, at least in her mind. The AP makes her feel all tingly and womanly like she hasn't in a long time. Yadda, yadda, yadda bullshit. It is infuriating to experience this as a BS because it is so stupid. For us, it's as useful as screaming at the theater screen as the victim in a horror film decides that now is a great time to take a bath.
You are officially her plan B. Well, until she figures out her AP is a worthless piece of shit. Once that happens, she will say that it was a mistake, she was confused, it was only sex, he meant nothing to her, or whatever bullshit she has to say in order to facilitate a soft landing. Now you are the plan A, the love of her life. In fact, she never stopped loving you and never really planned on leaving you despite the dreams of texts you have now unearthed that say the exact opposite. Conveniently, those turn out to be lies she told the AP to keep stringing him along for the ego kibbles. You know, the stuff that made her feel all womanly. Oh, and did I mention her sudden, overwhelming desire to protect you? Yeah, that's the reason she will keep the truth from you. It has nothing to do with her. It is a selfless act, like throwing herself on her sword for your sake. But all that sacrifice seems to hurt you and not her. One of those great mysteries I guess.
The AP might dump her once he realizes that she isnt worth it. This usually happens if you kick her out and she shows up at his door with a garbage bag full of her shit and a smile on her face as she proudly proclaims the she is all his and now they can finally be together... forever....which suddenly feels like a really long time. He might ask her to wait while he asks his mom if she can stay over. Affairs aren't as fun when real life intrudes. Kinda takes the thrill out of it.
I could go on, but you get the idea. Affairs are dirty, messy things that destroy lives. The very fact that she chose to have one robbed you of your agency, the right to navigate your life. As a result, she has taken all of the power in the relationship. You need to take it back. Not ask for it back, bloody well reach out and grab it, demand it. How you do that it up to you. It's your life, you decide. But you cannot decide until you start driving your own life.
Many people do the pick me dance. I certainly did. I tried to nice my way into a better marriage. It was a totally weak move and made me look contemptible in my WW's eyes, not like that manly go getter her AP was.
Ironically, once I got to the go fuck yourself stage, I was suddenly hot and sexy again. She was like a fish chasing those shiny lures. she was literally hopping from one best deal to the next, not realizing that grownups actually watch and keep track of this shit.
I hope things work out for you. I hope you take all of that good advice from people who are way smarter than me. It's a tough road, but on the other side, a stronger, better version of yourself is waiting for you. Imagine what he would say to you as you are starting out on your journey?