"Realistic" doesn't truly work because opposites are what make a dynamic, be it a big one or small one. Chad & Stacy being a couple can be a background thing, but for the most part their similarities don't really make a story.

I feel that if you want a good compromise of a realistic relationship that statistically happens a bunch in real life and opposites to attract - go for student-teacher age gap. IRL, students get groomed a lot or at least are attracted to older teachers and likewise, teachers love to toy or get into a legit relationships with their students. Furthermore, they are indeed opposites of some type by nature. The only thing you might find immersion-breaking is the teacher rejecting his sexy student's advances, truly a beta cuck moment.