She has no desire for him. She stayed with him for 20 years because you're supposed to when you take that vow in marriage,

Did she say that?

Next time...

1 - What marriage vows? Ask her to recite them to you.

Unless they aren't the usual vows the first thing you'll notice is that...

...there is no mention of children at all.

There is however a whole lot about being there for each other, which from the sounds of things vows she's long since abandoned .
https://www.theknot.com/content/traditional-wedding-vows-from-various-religions

In religious terms you aren't even married in such a case and can ask for an annulment. Even in Islamic law you can get a divorce in such a case. If she thinks she can take some high moral ground she's very mistaken. It's much worse than that she's picking and choosing which vow she thinks is important, there is no marriage vow that talks about children at all! And even if there was, it would need to be a vow whichdirectly contradicted everything that these marriage vows consider important. See if we're talking about what's best for the children, no one would ever think staying married in a toxic relationship is still good for the children. Maybe that's why no vows actually say anything like that.

2 - So now we've established by her own logic she's not kept her vows, and therefore in the eyes of all these major regions effectively not even married what right moral, religious or intellectual does she imagine she has over her husbands bodily autonomy?

Seriously, what possible argument could anyone come up with which doesn't immediately debunk itself?

If she wants to make an argument from marriage she's already proven herself bankrupt. Marriage as a civil contract in law just requires a signature, but "under god" it matters what you DO - that's what the vows are FOR.

Someone doesn't get to claim to take their marriage vows seriously if they're not actually following any of them.