Call each other on your BS
The happiest couples are also the most honest with each other. If one person is being selfish or irrational, the other calls them out! It feels good to have a sort of moral goalie in your life, telling you when you’re out of line. Couples respect one another for being so honest, and feel closer because they know the other person holds nothing back; they let them know when they’re not pleased with the other’s behavior.