"healthy romantic relationship" is what might be missing in understanding. There's a lot of unhealthy relationships out there, and they may even work. But they could be extremely dysfunctional.
I'm not sure if that saying, "All happy families are alike; each unhappy family is unhappy in its own way." works for romantic relationships.
Yeah you're entirely right about that, I should have worded it better.
Or a lot of them simply have no experience to speak of at all, given that a lot of current games seem to all build very specific and very similar characters to play the "dom" so to speak, so it could be that one dev had experiences with a dysfunctional relationship that may have masqueraded itself as a dom/sub dynamic, and the other devs simply copied that variant.
Regardless of what the reason might be, it definitely is grating to say the least to always encounter the same trope over and over again as a dom/sub dynamic can be incredibly good when done well, even in my eyes even though I don't really care much for it.
1 year at 18-19 is pretty huge, subjectively. Especially for a twin, and basically leaving things in an adversarial state. Whether she's good, or okay, or not, I hope is yet to come.
I hope it'll work out for them.
Also I'd like to second this.
Being betrayed by your twin during your formative years is sure to leave a pretty severe impact both emotionally and psychologically, even non-subjectively, our experiences during our formative years have the most impact on how we turn out as people if we're to follow science aswell.