AKA the default in many cultures throughout human history. Many unions are politically, economically expedient. People marry, pool resources, have kids. Physica

AKA the default in many cultures throughout human history. Many unions are politically, economically expedient. People marry, pool resources, have kids. Physically/emotionally cheat on each other on the side (well mostly the men), and it was understood you marry+have kids for the family, not yourself. Question is how societies can incentivize starting families for societies and not one self. There's been many failed fertility programs.