Two Capricorns together is a bit like two people who both insist on driving. Cardinal energy wants to be the one setting the direction, naming the plan, deciding when it is time to move. With most other signs one of you might eventually let the other take the wheel. With another Capricorn, you both know exactly how to steer, and neither one is naturally inclined to hand it over. That can turn into a quiet standoff over something as ordinary as whose career takes priority this year, who decides where the money goes, or which one of you gets to make the five year plan the household actually follows.
What softens this is that you are not fighting over different destinations, just who gets to hold the map. Same earth, same Saturn, same instinct to build something that lasts rather than chase a feeling. You will both understand, without needing it explained, why one of you cancels a weekend trip to finish a work project, or why the other tracks every expense in a spreadsheet before agreeing to a vacation. There is real relief in that. No one has to translate their ambition or defend their caution.
The risk is that you share the same blind spots too. Neither of you naturally says "let's just rest today" or "I miss you, come sit with me." Two people who both retreat into duty when stressed can go weeks running parallel rather than together, each assuming the other is fine because that is what fine looks like on the outside. This pairing works best when you take turns leading, on purpose, and build in time that has no agenda attached to it at all.