SAHMs: How much does your partner take over when home from work?

I'm also curious how this affects your home life and mental health. My husband worked a very demanding job when my daughter was 1 month to 3 1/2 months and that was the only time I really struggled and felt drained every second of the day. (My baby has CMPA and 6 other food allergies that she was exposed to through breastmilk so she cried for 6+ hours a day until we pinpointed all her allergens at 5 1/2 months) He quit and now works less than half of what he used to and when he gets home he takes over care of our daughter and half of the housework and now we are both in the best mental place in our lives. I really think that partner support can make or break that first year experience.