There's 2 parts to the IRD payment, and one of those isn't income tested at all (your tax break which is paid to you in cold, hard cash). It's a short-term thing, 6 weeks of payments I think, and you can receive it now, or at the end of the tax year.
In all seriousness, is DF good about the family finances, or it it 'his money' vs. 'your money'? Because if you're struggling to find money for baby stuff and household stuff, I wonder if it'd be worth you applying for it alone, and having it credited to your own bank account? It is money for the baby, after all.