OP I am very sorry about your situation and I hope my humourous outrage at your husband did not make you feel any worse.
OP isn't saying she hates her OH or he is abusive or that she wants rid of him. She is looking for a way to make him realise the enormity of her situation.
But she can't make him realise anything. She can try but she might not succeed. Sure, she doesn't want rid of him yet. But in the long run that depends on whether she can make him realise the enormity or not.
OP could he also be slightly autistic?
I wouldn't be totally surprised, it does run in families. But it wouldn't help the OP, apart from telling her that he isn't going to change, which by now she knows. She has three children to look after, not two, and in the long run she may be better telling the oldest child to leave home.
It's important for everyone in the family to take a break occasionally.
Yes it is very important, and he got a break for a whole day, then came home and complained he was tired. The OP doesn't even get a 10 minute toilet break. So what is your point?
And the OP has depression, sure, but it's probably not just PND. She has depression because she is living in an untenable situation.
He can't cope with the meltdowns.
Oh yes he can. He just doesn't want to and doesn't think he should have to. I mean what does he have to do except stand there til DS gets over it? It's embarrassing and unpleasant (btdt) but it's not hard.
DH thinks he's a hero for taking DS swimming every Saturday, but I do all the grunt work: packing the bag, driving everyone there, sitting poolside with the baby, getting DS changed, getting him dry, driving us all home. DH literally just gets into the pool with him for thirty minutes.
DH does not take DS swimming. You take the whole family swimming.
he's lovely but a bit crap.
So, your family "normal" is men who are a bit crap and women who look after them?