Both 1s are attracted to values, principles, a sense of responsibility, ideals, loyalty and the integrity of the other. They both have a strong desire to work on themselves, as well as the world around them. They share the same missions and beliefs and therefore feel mutually understood. They respect the high standard of the other and give each other advice on how to improve. They solve problems that could come up in their relationship with logic, reason and maturity. They trust each other and know they can count on the other to each respect their own responsibilities.
1s can be very judgemental and critical because they sometimes have the feeling that they are responsible for everything around them, and that can make them very invasive. If one of the partners is too critical, the other can bury their annoyance until a point where they cannot contain it any longer. They can also have difficulty agreeing on something if they both have a different point of view, because 1s are sometimes very tenacious about their vision of things and can be very stubborn thinking theirs is right. This can lead to a stalemate. As they are very hard working, and can care very little for their own needs, they can spend too much time on their professional occupation, without finding time for their relationship.