Sharing finances

I'm going for maternity leave in a week, I'll be getting 75% of my monthly earnings as a stay-at home mom for the next year. My S/o has said that I shouldn't worry paying my share of the monthly expenses and should do so when I go back to work. I'm not entirely comfortable putting all that financial burden on him so I told him I'd like to contribute for every other month instead of every month and he agreed.

Is this reasonable? Or should I finance monthly?