I have a LOT of experience of this. My STBX did this ALL the time, and he knew he could get away with it because I had moved back to his home continent with him and didn't earn much.
Looking back, it feels like he literally spent half the marriage ignoring me. It can't have been quite that much, but it was frequent and it was long-lasting. I think the record might have been three weeks. He had INTENSE anger issues, he fit almost every criteria of covert narcissism, and he was just absolutely horrible, interspersed with being the most wonderful husband. (And before anyone asks me why on earth I married him, he didn't do any of this until I was trapped abroad and vulnerable.)
OP, I was never able to make any difference with this behaviour. In my experience, nothing I said or did made it better. I think it's a stable personality trait that will never go away. Indoctrinated by my family into making marriages work at all costs, I only got away from him because he worked himself up into such a state of contempt and rage about me that he did the narcissistic discard after almost ten years. No one in my whole life has ever had the problem with me that he did. These covert narcissists burn with hatred for the person who is closest to them. They are vile, fucked-up puppies.
And they are the absolute WORST when you are vulnerable, as I was, and as you are. You say you couldn't manage without him, but if you were on your own, you would be eligible for help from Social Services. Attendance allowance, PIP, home helps...they are there specifically for people who have no help, so by staying with him for that reason, you're basically saving the system some money by putting up with abuse. Which is crazy. Also, you do have your children.
Looking back, I think it would have made a difference if I'd let him know that I would be fine without him and that I was thinking of leaving. They do this when they really and truly think that you can't leave.
Of course, even if he realises you might leave and it makes him shape up, this also begs the question of whether you want to be with someone who's like this towards people who are vulnerable and can't easily escape.
I am very sorry, OP. I suffered a lot with the silent treatment aimed at me; it's had a dreadful effect on my self-esteem and is a major reason why I will never marry again. This wasn't the only form of emotional abuse, either. It never is. It's left me with the distinct feeling that co-habiting or marriage gives someone way too much power over your well-being.
After he left, I was devastated and lonely, but things were peaceful at last. The divorce will happen this year, and you simply cannot imagine the sheer peace and joy and light I feel at the thought of finally being rid of someone who treated me so horribly for absolutely no reason whatsoever.
IME, you can't fix people like this. You either put up with them or get away for them. My exH got worse and worse and worse over time, until at the end, he would get SO angry at me over nothing that I really thought he was going to start hitting me. Luckily he left.
Wishing you the best of luck in dealing with what I know is a truly horrible marital issue.