Why does she have to stay at home? If he is imprisoning her at home (not allowing her money or access to a car, or preventing her from joining him at festivals and evenings out with friends) then that is serious spousal abuse.
Otherwise, it's a situation where the two partners may have different interests and a different social circle. She can join him at the festivals, go camping with him, go to the bars (they do serve non-alcoholic drinks, and he would need a designated driver anyway. Or, if those don't interest her, she can do her own thing -- whether that means visiting friends, going to a movie or the library or shopping.
Now, the 'not helping' is a different matter. If they live together, he should indeed do his share around the house. But that has nothing to do with her being pregnant. It's part of the life-time commitment.