When you’re in a long-term relationship, it’s easy to assume the grass is greener on the other side. (You know, the side where all your single friends are out swiping right and meeting new, fascinating people every weekend?) Stop thinking that. (And while you’re at it, ask your friends to share their Tinder horror stories.) As behavioral economist and TED-talker Dan Ariely explains in a new video from Google’s Modern Romance series, people doom their relationships when they start idealizing outside options.