Wasn't expecting this one:

I don't have anything really useful to say, but here's a perspective. In my small-ish town, a ton of people made decisions on where to go to college based on being in a couple. Sometimes this was a pretty big sacrifice, where the individual choices would have been different from the group choices. But they did it in service of the relationship.

To my knowledge, none of those couples endured. And my own perspective then, which has strengthened substantially in the intervening years, is that this was a dumb choice for them. When faced with a wider array of opportunities, people tend to grow in very different directions from their high-school selves, and imo this should be encouraged. It would be hard to overstate what a dipshit I was in highschool. I'm glad I was able to become someone else, relatively unencumbered. Although opinions vary whether I have transcended dipshit-ness.

Anyway, my point is that a cultural expectation that your high-school romantic relationship will not be a permanent one, overwhelmingly resembles the actual state of modern (e.g., post 1950s) reality, and an expectation that accords with reality is a useful one. If someone has found an epic love that ought to endure for all time, then fighting through the thin normative veneer around this issue shouldn't be too difficult.