Capricorns are drawn to each other because of their strengths. They are both very strong signs. Capricorn in astrology is the sign of success, achievement, taking on of authority and doing something with one's life which is public. Not necessarily that they are famous but they work well in the public because they can take on the control. They can take on the authority. The know how to delegate.
Now, in personal life, this can run into problems if you have two who take on authority and who need to be the achiever. Immediately Capricorn gets from another Capricorn that sense of security and stability. And this is a good thing because this is what they search for. Capricorn is Earth, Earth sign. In astrology, Earth stands for stability and a life of achievement and order and of dependability. They can depend on each other. But somehow the romance factor is missing. Neither of them is particularly evocative in their giving of affection. They tend to show love in deeds rather than in words. There is a kind of romantic element there that they don't show easily. For example, a Capricorn might give gifts but only once in a while. A Capricorn doesn't think of those light little touches. "Oh, let's bring home a bottle of champagne. Let's go off to Paris for a week." - this is not Capricorn's style. Capricorn is much too practical. And so with another Capricorn they can fall easily into a kind of routine, a rut, a sense that life is real, life is earnest. And a lot of the magic that a Capricorn can possibly find with a more romantic sign is missing. So they would make very good business partners if they can delegate who is in charge of what. They make very good sex partners because they are highly, or let's say deeply, sexual. But long term romance, there is an element that's missing.