Many relationships feel like 1 - 1. They total 0. Together you are more constrained. The world gets smaller. "You can not. Must not. Will not."
Some relationships feel like 1 - 2. They total -1. Together you are in a downward spiral. Toxic. Drama. Angst.
Few relationships feel like 1 + 1. They total 2. Together new options and experiences become possible. Even some extra-ordinary ones. "You rob the bank, and I'll drive the getaway car."
When you find the third kind make sure you recognize and appreciate it.