My spouse claims she doesn't, and never did like sex, and only initiated in our dating days "because men expect it". Back in those days, she told a different story, and the sexual activity was the most frequent and almost highest variety I'd ever experienced - there was nothing in her early behaviors that said she didn't like it, because she had certainly figured out how to do a lot of it.
The fact that she now claims she never liked it - well, I actually do understand the psychological underpinnings of a "people pleaser" and why they literally cannot tell the truth because they're driven more strongly to please people than to be honest with themselves - but the impact of having been misled, intentionally, for 10+ years is still in me -
Anyway, with this claim that she never liked it - and me still feeling lied to - if I were to find out she's getting it on with someone else - that would feel like a lie compounded upon a lie compounded upon the first lie - I seriously doubt I would make any attempt to reconcile.
As for splitting and recovery: With my ex, once I decided I needed to go, I put a few simple things in place. I had arranged a place to stay, and had packed enough clothing to go a week without laundry. I chose to deliver the message at a quiet restaurant, so we weren't surrounded by the stuff that was always around us when she was having a screaming fit. I had planted a second car at the restaurant. So, I gave her the message, placed more than enough money on the table to pay for the meal we had just finished, and left. I felt instantly wonderful.
Two days later, I wondered if I'd started a nuclear melt-down that would cause my entire world to collapse. Two weeks after that, I got laid off and felt very, very, unsupported and vulnerable. And experienced a panic attack - two of them. It's horrible, knowing, as a certainty, that you're either having a heart attack, or your brain is self-shredding or what the heck is this that's happening that's causing me to be blind and deaf and can't even feel if I'm standing or sitting? Thankfully, having survived two of them, I knew when the third hit, that I'd survive it, too, and that was enough to stop it. It was awful.
About one month after I'd split, I had secured a long-term rental. Alone and a bit lonely, but the process of setting up a home in a tiny apartment kept me occupied. A month after that, I borrowed a friend's truck and got all the rest of my stuff from the house. I left a note telling her that I had no claim on anything else in the house, so she could have it.
I had no desire for female companionship, and did something totally not like me. I went to church. And synagogue. And mosques. And Buddhist temples. I got infatuated with religion and mankind's need for it. And met friends of both genders.
I would say, overall, 60 days after separating from her, all thoughts of feeling guilty/bad/hopeless were gone. I had some worries about money, like would she come after me for something, but what, exactly, since I'd given it all to her? She never did. BTW, we had no kids, and by her insistence, also were not married...but were monogamous for 10+ years.
Within 6 months, I was enjoying life WAY better than literally any time when we were together.
Financially? Having simply given her everything meant no debt to her. It was over and done with. I had no debt, but also no income. Spent down my 401k in two years, got a lower paying job, but kept my lifestyle more modest. Being 36, single and no kids made me very popular with divorced women and single moms my age.
So...I'd do it again in a heartbeat. Don't want to, but if I found out the spouse was doing someone else...yeah, I'd pull the plug.