It can change over time. The deal that makes sense in house with toddlers may not make sense when the kids are gone and the primary breadwinner has gained many

It can change over time. The deal that makes sense in house with toddlers may not make sense when the kids are gone and the primary breadwinner has gained many responsibilities. Nobody anticipates this, because the patterns are set 20 years before. What I described is maybe stereotypical, but the point remains that relationships tend to stick to patterns even while conditions change.