Your partner is really able to act as anchor for your emotions. You tend to be more emotional than they do; you may get stressed out a lot and could even fly off the handle from time to time, overreacting to situations that upset you. They are able to help you get onto a more even keel.
Their grounding influence calms you down in times of heightened tension, and they are able to represent different sides of any situation for you, helping you to see why that cashier at the grocery might have spoken sharply to you or why your mother says those discouraging things whenever you call her on the phone. Your partner really understands your emotional side, and they even love you more for it. The way they see it, your emotional response to the world shows that you care, and they are happy to step up and help you through the difficult moments of life. This dynamic also applies to the happier moments of life, as well. You get all excited about something and your more grounded partner helps you to stay rooted in reality. That's an important function to learn, for yourselves and for the relationship, and even if this relationship doesn't last long-term, you are able to take these skills with you whatever you do next.