I believe it is wise to share a bank account with your spouse. If you don't, then that is a red flag about the state of your relationship. There's actually an old version of a wedding vow that says "With this Ring I thee wed, with my body I thee worship, and with all my worldly goods I thee endow." I think this reflects the biblical view of marriage and the idea of being one flesh.
Also, just to add to the conversation going on, my understanding is that during breastfeeding, oxytocin is released that actually causes the woman's memory of the pain of childbirth to lessen. I'm sure there are those who choose not to have more than one child because of the pain, but this generally seems to be the case, and biologically it makes sense that the body would have a mechanism like this in place that would allow or even encourage a woman to make the choice to have more children in the future.