I have a DP who does similar, if he’s watching tv and I need to ask him something I usually have to ask him several times, when he answers he does sound impatient and can be snappy.
I used to be hurt and angry thinking he was deliberately ignoring me, he will often say “what?” and then as I’m repeating he will answer, which is annoying.
He also repeats questions back to himself and it felt like he was trying to buy time to think of an answer so I suspected he was lying sometimes.
We had a few arguments and I said I felt like a nuisance to him and frustrated at being ignored.
My friend was round at our house one evening and she hadn’t spent much time with my partner at that point but had heard about our arguments, she was observing him through the evening. At one point DP was engrossed in something on tv, my friend started waving her hand in front of his face, DP just moved his head to see properly without speaking.
My friend has 3 autistic kids and has done a lot of reading and courses on autism and said we should consider getting DP assessed, we did as she advised and she was spot on.
I have learnt lots of different ways to approach DP and we communicate far better. He often does things like cough or yawn when he’s asked something, it just gives him more time to process things - as does repeating the question.
If your husband is good to you in every other way then it’s highly possible he’s not doing this consciously, you mention you have a child with SEN which can be hereditary.
If he is just ignoring you then that’s different and needs addressing! I know it can be upsetting and frustrating, if I ever have to give DP important information I make sure he repeats it back and sometimes we write it down or I text him. It’s much easier to live with now I know it’s not deliberate though. He