Friends like to share everything — but most people draw the line at their exes!

Earlier this month, Selena Gomez was spotted kissing The Weeknd shortly after he split from his ex (and Selena's pal) Bella Hadid. And judging by the dating histories of stars like Taylor Swift and Kendall Jenner, celebrities continue to prove they abide by a whole different etiquette code.

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Click through the gallery to see celebrity friends who have dated the same people.