How does the Betrayed spouse get from the place where the entire world is hostile and untrustworthy to taking power and believing all of their choices are going to be good ones when all of the evidence in front of them says otherwise? When the societal memes tend to offer condemnation rather than a good vision for life?
That's where you're missing it, man. The entire world isn't a hostile and untrustworthy place -- just the marriage. Just one-half of the marriage.
And that's dirt that doesn't stick.
Yes, the initial discovery of an affair is shattering, but it's a shattering of illusion, of a worldview and a fantasy future that's based on lies and projections of who one's partner is (I think you're like me; I think you have my best interest at heart just as I have yours.) That's not true. It's never been true, but marriages untouched by infidelity live inside that dream without any bumps because the illusion holds. Infidelity wakes you up, reminds you that you are your own agent, responsible for your own well-being and care.
Everyone's got an agenda. Even your spouse. Especially your spouse, because their agenda is the one that's going to come into conflict with yours the most often.
Once you know that, then you're free to engage in relationships founded on something solid, not on adolescent wet dreams of what growing old with somebody is supposed to look like.
That's part of the win, because once you understand your own agency, you stop letting circumstances interrupt the business of living. You stop putting yourself on hold while you wait for your partner to catch up, to see eye to eye, for your stars to align...because you understand that you've only got the narrative you write, and it's your story, not someone else's in which you play a bit part.
See, my wife's infidelity isn't the story of my life. It's flavor. It's backfill that makes me a complex and interesting character who can be empathized with. Shit, it doesn't even come close to be a core component of the narrative. It's got all the weight and value of an ex-wife joke.
And in the same way, it doesn't even inform my character or my future because it's not me. It's not my story. It's just somebody else's story that I read once upon a time.
You know that most people who know me are aware of my wife's affair. No one laid their pity on me, or their judgement. Their take on my story was "your wife is a fucking idiot". No one asked me what I'd done to drive her to it. Never have...and let me tell you, the stink of her behaviors didn't stick to me. That's part of her story, not mine. I'm not the one who flinches away from affair stories on the television almost a decade later.
I didn't need a redemption narrative, because I had nothing to be saved from, and the truth is, betrayed wives need it even less, because philandering husband is the only meme out there that tops ungrateful bitch on the popularity charts. (But that's okay. Memes aren't truth. They're expressions of our most base fears. They're Morality Tales in 140 characters or less. They're Reefer Madness with a raptor photoshopped in the background.)
Again, don't get me wrong: there's a ton of self-involved carping and agonizing by betrayed spouses in the wake of discovery. It's just a phase while the worldview is reassembled to include the new specks of truth. Most BS's emerge from this process unscathed long, long, long before their WS has even started up the hill toward Calvary.
SI is triage, not recovery. Not reality. It's a fantastic place for hearing the one important thing people need to put themselves back together: what you're feeling is normal. Once you get the hang of that, the rest of it's just a glide path to whatever new normal you invoke.
The people who struggle the most are those who get stuck trying to refute the narrative that's been written for them (I have to be Grace. Or I have to be Forgiveness. Or I have to be the Sacrificial Mother. Or I have to be the Bitter Divorcee.) Because they've become convinced they're an actor rather than an agent; a supporting role instead of the protagonist of their own story.
There is no objective evidence that says the world is hostile and untrustworthy. That's just meaningless emotion. It's sound and fury. It's the same bizarre awakening a newly expecting couple has to the sense that "everyone on television is having babies; all the shows are about maternity". It's selective perception.
It's bending the facts to fit the narrative they've been handed.
You get over it, because once you start opening up to others (that is, the 75% of the world whose marriages will also be touched by infidelity), you find yourself inundated with kindness, understanding, and peace. You prove out the trust of those who never broke it in the first place and remember that trust is real, that the war isn't universal, but localized to one or two aggressors (depending on how heavily you want to count the OP). A great many BS's struggle with this because (again) it's often the narrative their WS has been foisting off on them in the self-justification lead up to the affair, and then in the deflections of the immediate aftermath. (I wouldn't have cheated if you'd done x, y, or z. You're the cause of it. Here's some blameshift. Oh, and you've been a shitty spouse to me for years. If you'd just listened better, taken out the trash when I asked, sucked my dick more. This is all about you. It defines you. You're the root cause of it.)
And then you wake up from that shattered dream and realize, "Oh, that's all bullshit. And my spouse believes it because they need someone else to be culpable. They need to drag me down so they're not looking up at me out of the hole they dug for themselves. It's not me who is being defined, because it's not my narrative. It's theirs. They're projecting their definition onto me, because everyone hates to be alone and guilty."
Pay attention to the folks around here (BS's) who have been at it for a couple of years. Notice how little of their time they spend talking about their own emotional upheavals (in the absence of things like re-offending spouses or drawn out divorces) and how much time they offer giving comfort and perspective to new members.
Then I'd invite you to take a tour around the interwebs and read some of the other sites that have Wayward forums. It's interesting. Two years is just beginning to scratch the surface. It's still all about triggers, about learning to be safe, about confronting FOO and other lifelong dysfunctional patterns, coping behaviors, and things that have never been adequately addressed.
When our pastor offhandedly mentions infidelity on a Sunday morning, I reach out and take my wife's hand, because her reaction is visceral. I do that not because I feel any hurt, but to comfort the hurt I know she feels. I don't have an emotional stake in it, because there weren't any lessons for me to learn in it.
So, you tell me: which narrative would you rather be living a decade out? The one that's endlessly grasping after redemption (and all the great self-knowledge that comes along with it), or the one that never needed to in the first place?