When you start a romantic relationship, you go in with some idea that you and this person could go the distance — otherwise why would you waste your time?

Everyone wants to find the perfect formula to make a relationship last forever, but because every couple is different, a formula doesn't quite exist. That being said, there are some important traits that all successful couples share. Therapist Kimberly Hershenson told us what she feels long-lasting relationships have in common.

Words by Kristin Salaky at Insider.

[Photo via @tashoakley]