You don't waste a lot of time on small talk with this aspect between you. Instead, it turns your focus toward serious matters -- hard work, duty, responsibility. Your partner naturally slips into the role of your rock -- the comfortable, dependable person you know is there for you through thick and thin.
Maybe that's not the most exciting, romantic quality a relationship could have, but if you two are long-term, it's even better than simple romance or excitement. It's durability. It's a promise that you band together when the going gets tough; that you have a true teammate on your side when you need one. You give each other your best advice and even take turns acting as mentor to each other, when needed. You each bring the unique experiences of your own life to the table in this relationship, and you pool your knowledge and resources to create the best possible team. Of course, the kind of security this aspect promotes could also lead to a certain rigidity in your bond. You might get into patterns with each other that calcify over time because you just don't see a need to change -- hey, whatever works is fine with you, right? But do be careful not to get overly stuck in the same groove with each other. And remember to have fun once in a while. All work and no play... You know the rest.