I had never heard about vaginismus until I read your post. Have you thought about non-medical arousal? I have written stories about Christian marriage and sex. It's not Penthouse but neither is it how-to books or romance novels. It's real-life love stories that focus on everyday life and sex is part of that. I, too, am post-menopausal and that doesn't seem to have changed anything for me. It's worth a try and blessings to you both. "Saltair" by Mare Loch.
It's "40 Christian Myths about Sex." It's on Amazon: https://www.amazon.com/40-Christian-Myths-about-Sex-ebook/dp/B0B5XQ82S7/ref=tmm_kin_swatch_0?_encoding=UTF8&qid=1661365638&sr=8-1
Here's a twist on your idea:
In the next weekend or so, tell your husband you have a "meet-up at the bar" fantasy and that you hope he'll play along. "I'm getting dolled up and I'm going to the hotel bar on Saturday, and I'm hoping you'll meet me there and take me upstairs. Only do it if you want. But whether you go or not, I'm going. I'll be at the bar with a cocktail in that one red dress."
And then he has to decide whether he'll take this step of growth or not.
This exact scenario was described in the book Passionate Marriage by David Schnarch. Highly recommended when you're dealing with mis-matched sexual expectations.