Think of money as emotional currency. The struggle you two are having isn’t limited to who pays for what. They are issues of trust and shared responsibility. As your wife is pregnant I would highly recommend you do some pre-birth counseling with a family therapist who can help you think through the financial and accountability concerns that await you. Your anger and the financial concerns are symptoms of these unresolved issues, and a therapist can help the two of you find solutions together.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral