OP,
I think that your marriage is over and you clearly know it.
You are far to young to be settling for a relationship that doesn't make you happy.
Your husband didn't help when your son was born and unfortunately that put you on this path of distance between you.
It is a very common theme.
The road of resentment is often the precursor to no longer being in love.
I wish more men would realise this and not be so surprised when their selfishness comes back to bite them on the arse and they are surprised that their partner wants to split.
I think counselling would be useful if it helps you split up peacefully.
Do not accept him blaming you.
This is not on you.
He chose to do as little as possible and this is the consequence years later.
Start planning the practicalities of splitting.
Increasing your hours.
Selling the house.
It would be good if you can share the house peacefully while you get organised.
Him telling you that YOU will have to do everything is a perfect example of why you no longer love him.
Lazy and selfish.
Reach out to family and friends for support.
Your son will be fine if you do this peacefully and cooperate.
If he doesn't, it is further proof of how selfish and lazy he is.