Do a lot of men react badly when the subject of money is brought up with an newborn and woman’s mat leave?
Absolutely not.
Most men see the arrival of a baby as something to manage in partnership with the mother. The woman will carry, give birth to and often feed the baby. He can't do those things so he will want to play his part in other ways, i.e. providing a salary, getting involved in baths/changing nappies, doing a bigger share of cooking & cleaning, fending of visitors, taking the baby so the mother can sleep, late night runs for nipple cream, nappies, chocolate, or whatever else is needed, providing moral support and hugs.
Importantly, they won't expect gratitude for these things. They are doing them because they want to look after their partner and their child. Their only goal is that the mother and child are healthy and well looked after. They will do everything they can to minimise stress and wouldn't be knowingly creating money worries.
The men who do this aren't special in any way. This is the normal way to respond when you are going to become a father.
This sounds like light years from what you feel you could expect and that speaks volumes.
Bring your baby into the world surrounded by people who want to love and care for both of you. For you, I think this will be your mother, not your partner.