[This is going to be looooog, sorry in advance. I think it will be relatable for a lot of people.]
I'm sorry you went through that. I actually had a long reply typed up for you, but then my laptop ate it, and I had to walk away before I threw it. The gist of it was that the lack of understanding between you was a big issue, but I don't think a diagnosis would necessarily have saved your marriage, because he would still be ND and you would both still have conflicting needs.
I actually do know what it's like to be in those mismatched types of relationships. I'll give a tiny snippet of one -
This one time, when with a previous partner, he took my hand in public. I snatched it away. He was shocked. I said, "I'm sorry. I don't like that." He said "Why do you not want to hold my hand?" Again, I said, "I don't like it. It's a sensory thing. It really isn't personal." But he couldn't accept that, he said I had rejection him. I said it wasn't a rejection! But he just couldn't understand. He thought it should be different with him. "It's not a big ask. It would mean the world to me. Especially because I know you'd be doing it for me". But I couldn't do it. It's hard for others to understand that I feel like ripping my arm out of its socket, setting it on fire, then throwing it into a black hole when someone - anyone - touches my hand. It is not a little thing to me. I can't do it.
This discussion went on and on. Both of us explaining our feelings, but neither budging. I thought he was cruel for trying to coerce me into doing something I didn't want to do. He took offence at "cruel" and "coerce". He thought I was just proving, yet again, how little he really matters, that I just didn't want to do. this. one. little. thing. for. him because I only cared about myself.
His pain was obvious. But when he looked at me, he would have seen ice. Hard-faced. Iron maiden. But, believe me, the pain is there. It just comes out later. I felt like shit. I knew I'd hurt him. I knew he couldn't understand it. I knew he was adding this to my list of flaws. I knew it was triggering his insecurities. He always made sure I knew how worthless I made him feel.
On and on and on. In the end, the only way I could stop the horrific build-up of anxiety in me and my impending implosion, was to shut the conversation down and walk off. Which is another of my flaws, btw. I don't cope well with being cornered. "You always do this! Shut me down because you don't want to talk. It doesn't matter that I want to talk. Who am I anyway. I'm nothing. A nobody." He didn't understand that I literally could not talk any more. He could only see everything I did as stubborn choices.
This type of conflict was constant. It was a cycle. Something would trigger someone, we'd argue/discuss/debate/cry for hours, storm off, wait for the other to apologise, but eventually just go back to normal when it was clear no apology was coming. Rinse and repeat. Dying a little more each time.
That relationship nearly destroyed me. It was awful. We were awful together. He ended up cheating on me and blamed me for not giving him enough love and attention.
Now, my current DP has zero interest in holding hands, so that is never going to be an issue in our relationship. And he knows my love when I express it, which is usually something like me approaching him while he's working at the laptop and gently headbutting him. He smiles and says "I love you too." It's soooo fucking nice. There are no battles. No conflict. We have so much in common. We figured out what works and doesn't work for us. For example, we'll probably never live together because his breathing makes me want to stab him and he can't stand my untidiness. We don't take it personally.
My former partner would say I was an awful nightmare to be with. My current DP thinks I'm the bee's knees. I am exactly the same person. That is why I believe it is the combination of personalities in the relationship that determines if it is a good relationship or not. Not the neurology. Because I am as autistic in this relationship as I was in that other one. My behaviour is the same. Yet the relationships couldn't be more different. How is that possible if autism is to blame?
Sooo, my point is, your needs are your needs. Your ex-DH couldn't meet them. All a diagnosis would likely have done for you is make you feel like you had to suppress your normal, natural needs. But you should never do that, because that only leads to pain, conflict, and resentment, as you know. You deserve to be loved the way you need to be loved.
(I'll shut up now. I think this reply is even longer than the original for some reason.)