"Love triangle" is a pretty big misnomer, isn't it? Take any famous movie with one... Let's say "My Best Friend's Wedding": Cameron Diaz loves Dermot Mulroney. Julia Roberts loves Dermot Mulroney. Julia Roberts does not love Cameron Diaz! "The Hunger Games": Peeta loves Katniss. Katniss loves Gale. Gale does not love Peeta! We can go on, but you get our point. These are not love triangles, these are love angles: two sides, not three.
"Challengers" is that rare exception. Ostensibly about tennis, last year's hit features a real love triangle, with Tashi (Zendaya), Patrick (Josh O'Connor), and Art (Mike Faist) as its three vertices. Oh, watch out for steam on the court!
In the movie, Patrick, the once-promising-now-washed-up challenger, has the last name Zweig, which could be Jewish or goyishe German. In real life, O'Connor's name is as Irish as corned beef and cabbage, but he is surprisingly an eighth Jewish, and matrilineally to boot.
If you want another example of a real movie love triangle, there is Woody Allen's "Vicky Cristina Barcelona". Of course, that one might actually be a love rectangle... You know, we've spent too much time trying to picture all of this already!