A Tale of Two Lives
My grandma Ann was a sporty, almost athletic woman who loved to swim. She had learned home economics in an exclusive boarding school and was a highly professional housewife. She knew the nutritional content of every staple food by heart and spent all morning cooking and straightening the house, aided by a maid. The afternoons were for looking after the kids and/ or paying and receiving calls. Her husband, my grandpa, worked long hours in his own law practice. I am not sure how much time their lifestyles left for joint leisure. On Sundays there was mass - which my grandma enjoyed and grandpa didn't. And a bit of joint paying and receiving calls, according to a code that is no longer in use. (The maid would bring three business cards on a tray to announce a visiting couple: one from the wife and the husband each for grandma, and one from the husband for grandpa. Because a lady would not call on a gentleman.) My grandparents' marriage project did not include a big plan for joint spare time; that was a secondary question if a question at all. They were from the same broader region but otherwise not very much the same. If they had something you could call hobbies, grandma loved doing sports with the kids, and churchy things. Grandpa went deer hunting with his buddies.Their tastes and views differed in books, music, politics and culture more generally. I know for a fact they voted for different parties all their lives. Opposites had attracted each other very much, they married young. It was more important for them to economically complement each other; grandma's perfect running of the household including all nooks and crannies allowed grandpa to rise in his career, gain some notoriety in his profession and thereby build modest wealth for his family.
My other granny's story is quite different. After secondary school, she had learned a trade that would earn her money. She worked several years as a commercial and legal secretary, and ended up running the front office of a regional court. Having turned down several marriage proposals, she may have started to worry parents and acquaintances with her insistence to marry for love alone. Finally, at the (then mature) age of 29, she accepted my grandfather who swept her off her feet. This marriage was two birds of a feather flocking together. Her teacher husband loved soft classical music, historic books and endless conversations with friends at least as much as she did if not more. They were both deeply religious; they also voted for the same party. The part time nature of their work allowed them to spend some leisure together and many family photos show the two of them with the kids. They took vacations and loved adventurous outings on their two huge motorbikes before the war did them part.
Love and technological change
What happened in the few years between my two grannies' marriage dates? How come one follows a more traditional and one a seemingly more modern pattern? According to a paper by Lundberg and Pollack, two fundamental technical developments changed the lives of families in the first half of the 20th century: the surgence of household machines, and the pill. Before the advent of the machines, it was useful for partners to specialize, that is, for the husband to work and for the wife to look after the house and any children. Different skills sets and possibly different personalities in either half of the couple would allow this arrangement to work best. Tastes and likes were secondary, as Gary Becker's seminal work on family economics underlines.
Household machines alleviated a housewife's workload. A washing machine, even an antique one, allowed to handle multiples of the load that one could do with a scrubbing board on a basin. Coffee machines freed up one soul in the household to do something else for twenty minutes. This meant, that once the kids were in school, the woman could also go to work outside the house. Rewarded work made sense for women, and it made sense for their parents to invest in an education that would prepare for it. The pill (or other accessible forms of family planning) supported this trend as women could complete a full cycle of education well into their childbearing years. (On this one, also see Raquel Fernandez's work.)
Women grew into a position to earn and to look after themselves. They did not need a breadwinner but won their own bread. In these circumstances, marriage was no longer a must. There were viable outside options for a young woman, at least economically; if probably at a social cost.
Love and leisure
Marriages became more of a choice than a necessity. They needed a joint fun component, and a leisure component. Joint leisure was made possible by the technological revolution in household machinery. In this world, husband and wife want to spend time together that they both enjoy. They want to have conversations for the sake of them, not because they are needed. To this end, it is recommendable to choose a partner that is similar in education and tastes. A partner that likes to do the same things in his leisure rather than a partner that occupies himself most efficiently in a complementary manner while his other half is also efficiently occupied in her job. The more salient joint leisure is in your life, the more opposites distract.
The coupling of similar people is a feature we observe most strongly in contemporary marriages, it is called assortative mating. Partners are close in education and wage, and also height, weight and age. This does not mean that a regression on the evolution is impossible; opposites do find each other sometimes. But their marriages struggle to last compared to those of assorted mates. Nowadays, there is most often a tension between the technological and economic realities and the traditional relationship model.