The sex thing sounds simpler than that to me. I think she is using it to shift blame.
This is what WAW or WWs do. They will railroad the marriage and drive it to failure, but will attempt to engineer it in a way that they can blame you for it. That’s why if you approach her about alcoholism or smoking or slamming doors or swearing she will always drive it to the sex thing. She doesn’t want the guilt of this being her decision. It’s incredibly manipulative.
What should be ownership, ie: “I don’t want to stay married to Hoch or have sex with him”
Is manipulated into “We had to divorce because Hoch said he couldn’t have a relationship without sex.”
Classic move, in a world where fewer and fewer people take responsibility for their decisions and behaviour.