Two people meet at some point in their 20s, fall in love, and for some reason — a job, a grad school opportunity, whatever — decide to move to a place where they know very few people. Maybe they make some friends immediately, but more likely: they don’t. Maybe they already have a kid, maybe they start trying to have one (or a second) shortly after they move. They’re relatively early in their careers and spending a lot of time trying to advance them, so have very little energy to allocate to cultivating friendships that aren’t ready-made, e.g., a school cohort or friends at work.
Those friendships are nice but somewhat shallow, in part because these people spend most of their spare time with their partner, or working, or parenting. It’s hard to get a sitter and you don’t feel super comfortable just lugging your kid to other people’s spaces. It’s not that you don’t get out of the house; it’s just that when you do, it’s usually with your partner and kids. Meanwhile, maybe a parent’s health is deteriorating and you’re struggling to navigate care for them across the country. Or maybe you moved closer to your parents to relieve your overwhelming childcare needs….but now you realize your parents are your primary points of adult contact.