I don't have much to offer you other than understanding and compassion. My son is on the spectrum, and as a result, we ended up becoming very involved in the autism community. At one point in time, my wife created a non-profit for autistic adults to get help finding and keeping gainful employment, and then later in her career, she ran a school for kids with autism. We also have been involved in autism events and conferences, etc. My point being, we've met and have had meaningful engagement with a LOT of people on the spectrum, and heard thousands of stories of life's challenges for them and their families. The story you relate is all too common.
Bear in mind that, while no two people with autism are "the same", one thing that does remain somewhat consistent across the spectrum is that people on the spectrum think differently when it comes to social constructs, and often don't understand what's expected from neurotypical people, especially when it comes to relationships and emotional support. Autistic people tend to be "Self focused". I don't mean that as "an attitude problem" although that's how it comes off to neurotypicals. We would never accuse a blind person of "just not wanting to see", but that's easier for most people to understand. In a similar way, asking someone on the spectrum to "just behave like a neurotypical" is also not appropriate. They are wired differently. It doesn't mean they can't do it, but it is often a real struggle for them.
(Imagine a world where everyone else spoke pig-latin, and considered it just "natural and normal" to think and communicate that way. Now imagine trying to live, love, work, learn and thrive in such a world that never, ever, feels reasonable, natural or normal to you. Welcome to autism.)
The one suggestion that I do have for you however, is to seek out support groups. There are support groups for your husband of course, but there also support groups for family members of people on the spectrum, and I think you will find a lot of support and understanding there. You might also find answers through others who have struggled with the same things you are facing.
Autism doesn't make R impossible in any way, however, it does have its own challenges. I encourage you and your WS, if possible, to see this not as a barrier or a divide between you, but rather, as a common challenge you both face and need to overcome, and as a vehicle to start coming together as a couple in a new way. Since it is a challenge you both must overcome, do so together. By learning how to love and communicate with each other despite autism, you open the door to building new ways of loving and communicating overall, which is really the basis of R to begin with anyway. Do you know what I'm saying?
Best of luck to both of you.
Oh, one last thing, if you haven't already, there are some good books about "love on the spectrum" that might be eye openers for you both. "Love on the spectrum" is currently on NetFlix as well. I haven't watched it, but ironically enough, I met Dani Bowman who stars on the show, and she's still on my FB (along with a few other influential people in the autism space while at conferences).