Oh, gosh, MummyKWP, I'm so sorry about this situation.
However, practicalities. Look into temping, especially pay rates, and also look at childcare costs. Go to www.gov.uk/help-with-childcare-costs/overview and see if you could get any help with the costs.
Also, make a budget of unavoidable monthly outgoings.
Now, when you feel able to talk to your DH, show him the figures.
Will you be able to pay the bills even if you get 35 hours a week temping and have to pay childcare costs? If no, then he is going to have to do childcare 35 hours (plus travel time) per week, so that all your earnings go towards bills. Can you manage even then? (And this all depends on you being able to get full-time temping work). And what about after the baby is born? Will he be earning enough by then to pay the rent, utilities, council tax, food bills etc?
If he starts with the "Don't you trust me?" attitude, tell him it's not a matter of trust, it's a matter of you being worried sick about keeping a roof over your heads and food on the table and needing solid, practical evidence to reassure you.
Sorry, here I am, telling you what to do. I should perhaps rather say that would be my plan of action.