A bit of a different situation, but as a teenager I had a relationship with my much older and married teacher. In the end, through various permutations and after flip flopping, he went back to his wife and she took him back. She was very angry at him but even angrier at me, which is as you'd expect. She had been my teacher as well and it was a mess. I was 20 odd when it ended and had been 15 when it began.
Anyway, I'm in my forties now and look back on that period as a kind of bizarre madness that overtook my life for a while. But she stayed with him long term, i know because my husband crossed paths with her in a work capacity and she was apparently a fucker to work with. My husband knows about what happened with me and her but didn't tell her that he knew me, obviously. After a few months he and a colleague were moaning about this woman, specifically at the insane hours she expected from them, and the colleague (who'd worked with her longer and knew her better) said "oh ignore that, she only spends so long at work to avoid her husband, by all accounts she's in a terrible marriage".
My husband didn't divulge what he knew of her marriage, but told me. Okay, it's only hearsay, but that piece of info has come from somewhere and It made me so sad because this was 20 odd years later and she could have had a whole new life. They had no kids and she was 15yrs older than me, so had been 35 when she found out that about her husband. 20 years later and she was still with that faithless arsehole, living that life.
Meanwhile, whilst it was traumatising for me and a horrible experience, I've got a faithful and kind husband and am treated with respect in my relationship. Whatever they've been through since, she must have felt disrespected every day since, how could she not?
I know the set up of my affair is an unusual one, but the fundamental grimness of the affair is the same. Having seen it up close from the other side, I couldn't stay. I know the things that are done and said when a man cheats on his wife and remember them all too well. No one would ever do that to me and continue to have my time and love.
Much love and strength to everyone going through this. It's bloody horrible for everyone involved and may you find happiness in whatever you decide. But please do remember that ultimately, anyone who cheats on their spouse fundamentally has no respect for them and that's a tough pill to swallow.