You won't get what you want from him.
When did things get so bad?
Is he interested in the children?
Did he want children?
Is he different with friends or family members?
The absolute detachment from you could indicate he is seeing someone else.
Do you work at all?
I was thinking maybe he wants the marriage over, but perhaps financially it would be difficult, so he feels resentful and takes it out on you.
This isn't a healthy relationship and it will impact on your DC.
While you decide what to do, I suggest you turn your focus away from him and focus on being the best version of yourself...whilst making good memories for your DC.
Begging and apologising for doing nothing wrong is humiliating and the more you do it, the less he respects you. In his mind, he'll just see you as undesirable for begging and you boost his ego with the begging.