Our brains can usually override this process if we’re just not that into someone, but for all those middle ground cases where the right move is probably to move on and find something better, we often succumb to the chemical roller coaster and end up getting engaged.
For a woman who wants to have biological children with her husband, she has one very real limitation in play, which is the need to pick the right life partner by forty, give or take.
In our world, the major rule is to get married before you’re too old—and “too old” varies from 25 – 35, depending on where you live.
The rule should be “whatever you do, don’t marry the wrong person,” but society frowns much more upon a 37-year-old single person than it does an unhappily married 37-year-old with two children.
Unfortunately, the way society is set up, fear starts infecting all kinds of otherwise-rational people, sometimes as early as the mid-twenties.