When is enough, enough? Ds4 affecting marriage

[ADarkDarkSomething]

My son is 4, only child of me and husband (I have adult children with a large age gap, DS4 is his only).

Son is lovely, popular, bright, nice personality and can be very sweet, but in the other side, he has constant tantrums and attention seeking behaviours. Mealtimes are absolutely dreadful, like a war zone. He whines and whinges, my husband gets angry and if I say anything, it is All My Fault.
DS has slept in our main bed with my husband for two years now. I want my marital bed and room back, but my husband seems to be fine with the way it is because it is the 'only way we get any peace'. So here I am, on a mattress in the spare room. I might be being petty, but even if DH and I have a (now fairly rare) hug in front of my son, he runs over and pushes in. Sex almost never happens.
I am fed up with this and my husband's attitude that it's OK. I want to assert more boundaries, steer Ds off ( kindly) when he tries to push in, decorate the room next door to us and start the transition to his own bed but my husband thinks it's unnecessary. For my part, though, I now feel like a cook and cleaner sleeping on a mattress and that the relationship with my husband is slowly getting snuffed out. I even asked if he wanted a divorce and he looked at me like I was crazy and said 'Of course not!' But he can see we aren't having any sort of personal private life together.
Not sure what to think or if I am being Unreasonable but would be good to hear views.

@ADarkDarkSomething

"This kind of behaviour is what breeds narcissists"

Can you tell me a bit more about what you mean? It is something I have worried about a lot. At his best, my son is completely adorable and lovely, but at his worst, I fear he is becoming spoilt and entitled. He was rude about his birthday presents, for example, to my great dismay. Of course I don't want to reject him or break his spirit, but I do worry about his attention seeking (school have remarked 'lightly' on the same subject)
H and I are from different cultures so
perhaps this is in play, I am
not sure. He's also an only, I am one of a large sibling group.

www.google.com.au/amp/s/amp.mindbodygreen.com/articles/how-to-make-sure-you-arent-raising-a-narcissist

In your case I think it's the father (you're partner) rather than you being the issue

@ADarkDarkSomething

Thank you, all. Well, I have been very strict tonight and ended up not reading stories because he wouldn't stop jumping and throwing cushions, so I left him in bed. Felt mean and rotten when I came down though. Argh!

Good start OP.

When you feel bad imagine how you are going to feel when he starts trying to make friends at school and he starts his bratty, spoiled, demanding behaviour and the children and their parents avoid him because he is too much like hard work.

I have seen children like this over the years and they are avoided.

Too many lovely children to play with and I always told my children AVOID.
I certainly wasn't going to be arranging playdates with children that are hard work.

I don't blame the child because it is the parents who have failed if children turn out like selfish little terrorists.