Natalia's ex is Post Malone. But they parted ways about 10 months ago just a bit after "Stoney" was released. Austin's fame became more important... and Natalia resumed her lonely life.
What happens in Vegas stays in Vegas.... unless your Post Malone and you end up marrying the girl you were into all night who is now booked for the final spot for his birthday celebration in Greece, the same trip his now very recent and unknowing ex-girlfriend is also attending...