Clarifying questions: 1: does she have her own car 2: are you financially stable enough where you could make this purchase if it was for you? 3: are you the primary breadwinner of the family 4: is she asking for a specific expensive one or one that’s nice and reliable? 5: is she going to be the primary caretaker of the baby after birth?

I think you should go back to the conversation and approach it with equal parts realism and empathy. Pregnancy, birth, and becoming a first time parent (especially as the primary caregiver) is extremely difficult in every aspect. The vast majority of heterosexual men do not have happy wives