These two types get along well because they are both autonomous and value logic and reason. The 1 admires the intellectual perspicacity and the theoretical reasoning of the 5. He also appreciates his calm. The 5 value the rationality, the organization skills, the perfectionism and the discipline of the 1. Both are quite mental but have different ways of thinking, which animates their relationship with many long debates that stimulate them intellectually. Both are autonomous and respect the personal space of each. They do not tend to express their affection, but they feel it indirectly.
The 5 is more self-centered while the 1 is paying more attention to others, which can cause them conflicts of interest. Although the 1 is quite autonomous, the 5 is even more so, and this even greater need for personal space of 5 can sometimes make the 1 feel pretty anxious. Since neither of these partners is comfortable with emotions, the relationship can become cold and distant in the event of emotional conflict, during which both may tend to escape into their professional lives.