He wants attention and knows he gets it if he’s hurt or sick. I’ve also seen him fake hitting his head then run to me saying Mummy I hit head. Or fake jamming his finger in the door!
@Molocosh
You are aware of the problem. It's the attention you give him.
What are you doing about it?
How about a cheerful 'Whoops! That must have hurt!' And no more on the subject.
Wrt the sticking his fingers down his throat - do you still respond by running to help when you hear the choking noises?
How about only going up if you hear actual puking, and then only dealing with the mess, along with a reprimand to DS and escorting him back to bed with no more interaction?
I think you are feeling a lot of guilt about restricting attention to DS. He is dependent, yes, to a certain degree and in certain areas of his life. Physical dependence continues for many years.
But you need to encourage emotional resilience or his development as an individual will be compromised. You need to participate actively in moving him onwards and upwards, and to do this you need to break some of your own habits and critically examine some of your instinctive responses.
I highly recommend a book by Pamela Druckerman, an American living in Paris who chronicled her culture shock as she observed the French approach to parenting and sought to get to the bottom of American and French babycare practices.
In short, American (and British) = guilt, French= no guilt.
The book is 'Bringing up Bebe'.
I think you would find it thought provoking, maybe even inspiring.
Your relationship 
It is a huge shame that your H has chosen to apportion blame for the situation that has developed, and to arouse your protective instincts in dealing with DS. Your protective instincts are part of what is keeping you from establishing a healthy separation between DS and yourself, so he is actually making this situation worse.
He needs to promise no more shouting, expressions of frustration or anger when dealing with DS. He needs to acknowledge that the habit he has of apportioning blame for this situation is not helping to cure it, and recognise that you were doing the best you could with what sounds like a difficult baby. I have had one (out of five). They are nobody's fault, but there are ways of dealing with them that move everyone forward.
Unless your H correctly predicted how all of what you were doing way back when DS was a little baby would pan out, and offered to help establish a good sleep regimen for DS, he is just being mean to you, and the hurt his words are causing are a threat to your relationship.
The two of you need to sit down and talk about your needs when it comes to physical touch. Use 'I feel' sentences, with no blaming and a conscious effort to avoid the toxic 'You never...' and 'You always...'
It is very important that he understands that not every hand hold or meeting of eyes is a sign that you want sex. You need to understand that wanting a sexual relationship isn't a crime (though the way he is going about getting that is a problem). The way forward is to find a way to meet everyone's needs and the two of you need to create a safe space to talk about all of this.
This may sound odd or stupid, or even impossible, but bear with me...
Maybe having a realistic expectation that the two of you will have sex on a certain night every week he would be less inclined to hop on every little indication of togetherness you signal, which seems to result right now in frustration and resentment for him and disappointment at the misreading of signals for you.
Here's the weird bit - start by scheduling sex for, say, 11pm Saturday night come hell or high water, with DS completely ignored at that time. Build up to two scheduled nights per week, and take it from there.
For his part, he will return a hand squeeze or a smile or a back pat or a kiss on the cheek, or even initiate all of this with no expectation of sex to follow.