Maternity Leave

So my fiancé and I got into an argument the other day. I'm due in October and because our work doesn't offer maternity leave I get the fmla. He's mad at me because we just spent money on a car we needed because we've been using his moms car. It's been 3 weeks since we got the car and now he wants to buy a freaking motor bike. I said no. We need to save up for When the baby us here. And I want to save half my paychecks because that's 4 months if leave. Now he's mad at me because I said we don't need a bike if he wants it we can save up for one but we're not buying one and spending all our money at once. So to get back at me he says well I don't think you need four months of maternity leave. You can go back to work after a month. Like what the hell because I want to be responsible and save our money for stuff like a car seat a crib other baby items he's going to throw a tantrum.