The achiever meets the benefactor.*
This can work quite well, provided that Cancer has no objections to the grand projects Capricorn frequently gets involved in and Capricorn allows Cancer to be in charge of their private sector.
Once they become attracted to one another, they're eager to solidify their relation and don't mind the prospect of building a home together. A family is fine, too.  They mean it when they commit.
But they continue to compete about the leadership and about whose plans should win when they have conflicting intentions. The relation can be noisy at times, when the two strong wills collide, but they can take it. It's a process by which they improve their relation, even when it seems like the very opposite.
Actually, they are both stimulated by it.  A lasting peace would make them confused and worried, sensing that something is missing and worrying that their love is fading.