Today I pledge to get up, stand up straight and start digging my way out of this nightmare. I don't know exactly what that looks like but I'll start with getting through my work day and then booking a ticket back to the US for a couple of weeks to gain clarity and line things up.
That's a great idea. How soon can you arrange it? It seems like just this little bit of distance during your brief work trip has really empowered you. If so, a few weeks away might bring you complete clarity of mind.
...I have spent far too much time trying to understand my role in this, how it got to this, what I did to my relationship to make him do this and how I have let it get so far.
The short answer is that you didn't do ANYTHING to deserve being treated this way. All relationships have issues and problems, all people have issues and problems... but only some choose deceit and betrayal.
I've spent a great deal of time researching infidelity, trying to understand what happened to me. Frankly, my WH's Craigslist cheating binge of four years ago wasn't his first time. The first time was ten years prior to that and didn't involve live partners. It was all online. The people involved were real. Hell, he was giving money to some of them. But I caught him out about two weeks before he was set to meet up with one.
At the time, I really bought heavily into the "unmet needs" model (which is still popular with some therapists). The unmet needs model tell us that we all have emotional needs which are being met (or not) within our relationship, by our partner presumably. Infidelity occurs when those emotional needs aren't being met correctly, according to these "experts" anyway. So, you can imagine how I reacted, right? I doubled down on my "good wife" game, empathized with how pitiful and lonely my poor WH must have been, poor muffin.
The problem is that cheaters don't cheat because their "emotional needs" aren't being met. They cheat because they use PEOPLE to spackle up the voids inside. We're meant to be self-fruitful in matters of personal satisfaction/happiness. That's what being a whole and complete adult is all about. But this is what we mean by "broken". These are people who can't be satisfied on their own, who lack moral boundaries (ie. not enough empathy to keep from hurting others, read "character"), and who feel compelled to get their "needs" met even when doing so conflicts with their stated values. These are people whose excuse is "s/he MAKES me feel...", because external approval takes the place of the internal approval they can't muster on their own.
So, you begin to see that this couldn't possibly be anything to do with you. It's not about what you were doing or not doing. It's not about the size of your boobs or how good you are in bed. It's not about being too skinny or too fat. It's not about cleaning out the sink or doing his laundry. It's not about you at all. It's about the cheater... always about the cheater.
What hurt me so much in the beginning (and still does when I'm having a bad day, tbh) is the thought that my WH could do this to ME. I had spent over 30 years with him by then. Through thick and through thin, sacrificing so many things I wanted for myself so I could support his career, give birth to and raise his children. Hell, there were times when he was eating the meal I cooked special for him while he was sexting an OW. He fucked one of them on my birthday, then came home and handed me a card which read "hope you find your happy place". My DDay was on Christmas when I woke up to find him gone for the first time in more than 30 years. It was sooooo abusive. Of course I was bogged down in "how could he do that to ME"?.
This is where we have to remember that it's all about the cheater. It was never about me. Just like the OWs, I was a useful object.. spackle for his broken places. And it's pointless to get down on myself for not seeing that earlier because why would I? Normal people don't think like that. Hell, even the cheater doesn't think like that. They rationalize their behavior to justify their actions in sometimes what is quite frankly astonishing mental gymnastics. It was never about us. We couldn't have seen it coming.
That's not to say that every situation is hopeless. But it is why so many of us talk about true remorse when we're talking about the potential for recovery. True remorse can lead to real empathy and real healing. It's imperative though that the WS is willing to repair the deficits in their character which allowed them to cheat and also to learn how to be internally fulfilled without stuffing people into the cracks.
So, why is your active cheater playing sadistic games with you? It's simple, albeit not easy to hear... You are a useful object which adds spice to the illicit nature of the affair. The risk of getting caught pumps up the adrenaline-packed biochemical cocktail which is the addictive part of the payoff. Meanwhile, triangulation affirms his centrality in two women's lives. He feels important, attractive, sexually and externally affirmed. The interior insecurities he can't manage to assuage on his own are spackled in by two women. And the OW is getting the same thing out of it, plus the added bonus to her pathetic ego of competition, getting one-up on you. Once you've eliminated the triangulation by getting out of infidelity, you've taken risk out of it, and risk is the driving force of the biochemical cocktail which made it all so tantalizing.
Sometimes the cheater comes running home. Sometimes they're actually willing to do the real work required to be a good and safe partner again. Sometimes they run off with the paramour, limping along for years and making occasional bids to get that triangulation going again. There are all sorts of potential outcomes. But (and here's the crucial "but")... your eyes have opened and you have AGENCY. You are in a position to say who and what you'll allow into your life, as well as how you'll allow others to treat you. Once you've detached enough to view adultery with a clinical view, you can see all the gears moving, why these people do the things they do, what compels them, and what the payoff is. But more importantly, you can let go of the notion that you could have influenced or changed it. We can't control other people. Surviving infidelity teaches us the fullness of that life lesson. We can't control other people.
Sorry for the long rant. I do hope you find something in there which strengthens you though.
((hugs))