Having children in the household brings no increase in life satisfaction for men - and an increase in women's life satisfaction only once the children are attending school. What's more, women with children are significantly happier if they have a job, regardless of how many hours it entails. These are among the findings of research by Alison Booth and Jan Van Ours, which explores the degree to which family happiness is influenced by the number of hours that men and women spend at work.
As you say life satisfaction is somewhat difficult to pin down and measure. Ad astra per aspera