Romeo and Juliette is also about a 13yo girl and 15yo boy, so it's hardly a role model story for a bunch of reasons.
It was not a "golden story" about romantic love when it was written - everyone ends up dead because of their obsessive love and inability to consider anything else!!
In the social context of the time, it was far more about the dangers of obsessive love and lust, unrestricted by social conventions and family input. We have romanticised it over the years to something it never was.
Arranged marriages for property and alliance reasons (not love!) were the norm in most societies for most of history. And the pair bonds were for similar reasons - pre DNA tests, you wanted to be sure that your wife's children were also biologically yours, so in a pre contraceptive and pre DNA society that meant you had to restrict who people (women!) slept with to have confidence in bloodlines for the purposes of inheritance.
This is also why it was normal and accepted in much of history for men to have mistresses and as long as they paid for them, and any resulting children, it was not much of an issue because it didn't affect bloodlines and inheritance.
We over-emphasize and romanticise the importance of romantic love in the past - it really wasn't a significant factor, and yes, it came up in poetry and novels, but largely didn't reflect people's day to day life in many ways. Chivalrous love, for example, from the medieval period, was never focused on one's spouse...
Plus with the number of women dying in childbirth, multiple sequential wives was often a reality.
There are actually also quite a number of societies that don't/didn't practice pair bonding - mostly nomadic ones where property/inheritance was not the major issue it was in other societies. And these were largely stamped out when the Christian missionaries came, because they didn't approve and believed there was only one "godly" way to do relationships .
But interesting as all these points are, they're kind of irrelevant.
Some people want to organise their lives in certain ways. As long as people find other people who want the same, and are honest, open and respectful about it, then it's really none of anyone else's business. We each have our own experience of "love". It's not for anyone to dictate what anyone else's experience of that is or should be.
You want monogamy - fantastic, I wish you every happiness in that. You want polyamory - great, I wish you just as much joy. You want to fuck about with lots of people - as long as everyone has fully informed consent and happily agrees to it, also great.
Generally, no-one in the minority groups is trying to make people live in a way they don't want. Whether that's being vegan, religious, poly, childfree, gay, or a million other life options. So if you're part of the majority, please extend the same courtesy and try to avoid making derogatory comments about things you don't personally understand or want to do.